What follows is an imperfect but hopefully a correct response:
There is no more 'eurogatwick'.
All shorthaul flying is now known as 'Eurofleet' (EUF). You have EUF at LGW, and EUF at LHR.
'Mainline' refers to those staff under the 'main'/original BA contract. All EUF LHR and longhaul crew at BOTH airports are on the mainline contract.
Only EUF LGW crews are under a DIFFERENT contract, and yes, it is much LESS than everyone else. That's because EUF LGW was formed from the ashes of Dan-Air (an ex-airline!), and BA decided to preserve the (less expensive) labour conditions from this ex-Airline.
EUF LGW is basically a SUBSIDIARY company, with different terms and conditions for cabin crew. EUF LGW crews are paid on an hourly basis, and work 4 sectors a day, whereas their mainline colleagues at LHR usually only fly 2 sectors a day and get paid more because they are not paid hourly, but under a different system.
Maybe the difference is irrelevant to you, but if you have a choice, it would be wise to avoid LGW, as you will not be on a great contract compared to your collegues at LHR....
And just to add a little more complication, longhaul flying at LGW 'mainline' will now be merged with EUF LGW, so now ALL crew at LGW will be flying both short and longhaul, but on a similar hourly contract.
In other words, avoid LGW completely...
What I think is happening is that management are desperate to reduce employee costs, and because of strong union reps at LHR, they are introducing new (poorer) working conditions at LGW first....I am pretty certain that sooner or later, they will attempt the same at LHR
