Correct but both operate to MAN, I'm talking about establishing a proper base at MAN, with a serious choice of routes.

No, that's not what I said. By comparison, easyJet have a LGW based fleet of NEOs. WizzUK, likewise. What I said was BA's finance team apparently cannot see an ROI on going to IAG to ask for new NEOs for Euroflyer as the business case isn't strong enough. Could be wrong, but with so many aircraft on order.....
BA are the oddballs in that they don't fly new builds in market, even Jet2 bought a new fleet of B73Hs and are taking A321Ns as we speak. If LGW did as well for BA as we'd all like to hope, even me, there would be a Club Suite refresh plan and new A32Ns / Maxes coming. Neither is happening. It's not a LGW problem, it's an inability of BA to make LGW work well enough for them on it's own merits, like everything else, LHR comes first as that seems to be where consistent money is made for BA, others do way better. Follow the money?
Jet2 do loads of seat only, it's why half the fleet is in grey and red, I flew on one last weekend on a seat only basis on a short break to Spain.

I share your frustration regarding BA at Gatwick. I totally agree that with more investment they could do well. However, as long as Heathrow dominates their planning there will be little change unfortunately. Their dominance at Heathrow also protects them somewhat.
Perhaps as Heathrow becomes even more constrained, and Gatwick does bring its Northern runway into routine operation, they will have to look at things again. At recent results meetings it has been said that they are watching developments at Gatwick very closely. They are also keen to have all their leased out slots at Gatwick returned to them by summer 2025.
The increasing number of full service airlines beginning services from Gatwick is also an interesting development and I am sure BA are keeping an eye too.

Which of the new entrants at LGW would BA be most concerned about?

Not 100% certain, but Singapore airlines could draw people away from LHR services as could Cathy Pacific if they return.
Air India seems to be doing well on their services too. You also have Saudi and Ethiopian (The later offering good connections throughout Africa).
The Chinese carriers offering 3 to 4 flights daily and of course Emirates and Qatar Airways.
There are also short haul entrants too, such as Lufthansa and Swissair. They also obviously don't want to leave the SH market to easyjet. as why bother with BA Euroflyer? They are taking back all the slots leased to easyjet since the pandemic by 2025.
Having said that they appear to have given easyjet an almost free run on domestics from Gatwick. BA were carrying 300000 to 400000 plus passengers annually to and from Gatwick and Edinburgh up to 2019.
I don't believe they have all disappeared, even allowing for less business travel.
Of course they remain determined to protect their Heathrow loads and yields. I wonder if BA Euroflyer are really that free to try additional cities from Gatwick without mainline worrying about impact on their services from LHR.
I also didn't say they were concerned, rather just keeping an eye. However, they did react when Norwegian expanded some of their transatlantic destinations from Gatwick a few years ago. They seem less worried about Norse though.
Just a few random thoughts.

They also need to be mindful of their impact on LCY, the domestics from LGW were removed but point to point connectivity was kept out of LCY. Now even CFE are having to densify the Embraers to survive as most sensible companies offer hybrid working and so less need for business travel to a glass tower in East London. If they let BA Euroflyer off the leash and funded some growth, they'd impact LCY negatively as well as boosting LGW. I note Tom Stoddard is running both LCY and LGW operations, hence for BA it's LHR and "the rest". It's a tricky balance! It's the same dilemma Barbara Cassani faced at Go-Fly, , she could really have built a successful business FOR BA if they'd been less concerned about the impact on an existing short haul model that wasn't growing and subsequently almost collapsed.

Compare easyJet's ability to grow STN/LTN/LGW in parallel with the same thought process, BA can't do this as a critical mass of traffic MUST use LHR to feed long haul and so they must prioritise accordingly.

Complete nonsense. You say BA Euroflyer is similar to Vueling / IB Express - no it is not.

Vueling is a standalone low cost carrier, they are allocated NEOs by IAG for fleet renewal and expansion.

Iberia Express runs routes out of Madrid to assist IB in competing with the low cost carriers. The business case notion falls flat again. They will be allocated NEOs with no less ‘preference’ than mainline.

It’s nothing more than BA using the NEOs at Heathrow to save money, don’t know where you have gotten this from?

Ok, so why not allocate some new A320/A321 neos to Gatwick in parallel to LHR?

Does BA Euroflyer have it's own AOC like Vueling and Iberia Express? Yes.
Is it branded the same way as it's parent? Yes, see Iberia Express?
Are they paid less? Yes, as per Iberia Express. I2 was set up by Iberia with the threat that every single new route and airframe would go to I2 and IB would be allowed to wither and die as I2 grew UNLESS staff agreed to major concessions. The public branding would be almost identical, that's why "Express" is in tiny letters.
The NEOs are a multi million pound CAPEX fleet renewal, they are placed where IAG agree they will derive maximum ROI.
IAG do not "allocate" aircraft as a benevolent daddy figure, each OpCp has to make a business case as to why they deserve them! It's competitive and a case must be made. Now it turns out that A320 CEOs are a pain point at LHR due to noise considerations meaning they're more expensive than they were, which is why almost everyone now flys the NEO to LHR, BA doesn't exactly have THAT option as they have a based fleet of CEOs.
Same reason there's no Club Suite coming to LGW, the investment goes where the ROI can be made up faster, LGW is relatively weaker than LHR for BA, hence LHR always gets first dibs on new equipment. If BA gets 50 new NEOS, all 50 would be expected to start their life at LHR. The only short haul narrow body I can remember that BA ever took delivery of at LGW was the very last Dan Air ordered B737-400 over three decades ago. Before that we're talking British Airtours B737-236s.
(I think that's right?)

Skipness One Foxtrot, I asked that question 'Ok, so why not allocate some new A320/A321 neos to Gatwick in parallel to LHR?' to sort of question/challenge the suggestion that the only neos went to Heathrow as they were cheaper to operate from there. I know the actual reason, which, in my opinion, is as you describe.

Whilst BAEF may have a degree of autonomy, I just don't see a MAN base happening.

BA's main priority is long haul on the North Atlantic and other key markets. In terms of growth, all the signs from IAG are that BA will be focused on rebuilding long haul capacity in the coming years.

Short haul aircraft orders for IAG seem very conservative and with BA still leasing out slots at LGW & LHR, it's not as if it's exhausted capacity in London. The brand recognition in the South East is stronger - watching people tap in and out on the Tube it seems that half of London has a BA Amex card.

Also, the last thing BA should be doing now is anything that distracts it from operations in London - hopefully this summer will confirm it has turned a corner.

I’ve read articles stating that there are over 500,000 people with a BA Amex and they put through more than a billion pounds a month so it’s not unlikely a lot of tube passengers could have one.

In the US nearly 1% of the GDP goes through a Delta Amex so BA still have a bit of a way to go.

It's a slightly inflated number but Amex can't book transaction volume as revenue, so it's not a million miles off https://viewfromthewing.com/is-delta...4277%20billion.