LGW commands were at 4-5 years in this year. Who knows about the future!
Would it be fair to say that Gatwick commands certainly aren't the BA norm, for all sorts of reasons, and that is a situation that is unlikely to change?
How about the long haul fleet?
I assume you mean time to command? If so who knows? Last few decades it's been 15 - 20 years'ish plus depending on the fleet you are bidding for. Difficult to predict going ahead but IMHO (that's all it is) that's what you still need to plan on at the very least and I guess hope it comes down. There's probably going to be a bit of a retirement bulge coming up but OTOH you've still got a sizeable cadre of the Prestwick cadets in the LHS, next in line are the '90's and the '00 DEPs, and their replacements (eventually) will be the DEPs and FPPs who are already "in" in significant numbers.
I'd put money at time to upgrade to a Long Haul command staying at or above 15 years for quite some time.
(edit to add: I see Flap 33's more pessimistic than I am but also probably more realistic, I'd certainly echo his/her final comment - FWIW I was told 7-8 years for a 747 command when I joined as a DEP..it actually took 16)