All I'm suggesting is that a semi-fast train service via Guildford would combine both LHR & LGW requirements. Simple really !
Sorry what market does a LHR/LGW rail connection serve?
However, it does seem a little unnecessary that BA and VS operate flights from MAN to LHR just to feed long haul (and probably only one or two specific long haul routes I would be willing to bet) when they could operate a couple of 777's or even 787's out of MAN and free up some slots.
Don't bet, you'd be wrong. The domestic connections offer service across most BA short and long haul connections, that's the whole business model. Read the threads on MAN and BA, and MAN long haul. The main point is that BA's MAN operation died as it was point to point whereas all other long haul at MAN is spoke to HUB. Clear and apparent difference and a huge driver on profitability.
They operate feed to LHR as they HAVE to feed long haul.
Means they won't have to operate a large presence at LGW, and could instead have a smaller one at MAN?
There is almost no link between moving from London's second airport into the premier facility and expanding long haul out of MAN. It's all been tried before and there are numerous threads on why it ended.