Thanks for all of this information - makes most of the process very clear.

Quick query - re fast track security access after you arrive INT with a UK connection J or above.

Does it still exist? And if I exit landside and then re-enter airside - does that benefit still apply or does it depend on what class your dom ticket is in? My Dom ticket on an F redemption going out apparently gives me access to the galleries lounge (selling class U) so would that give FT anyway?

Thanks