The destinations they fly to and from T3 are to a rather random handful of destinations in my eyes, but I suppose there is some logic, which I am sure someone can explain...
I am flying to LCA in November and was really looking forward to the T5 experience (as not used it yet), and wasn't until I checked further into the info, my flight is operating from T3.

(Only found this out when I was just about to book my airport parking, so pleased I checked as a trek from T5 to T3 at 5am would not be fun!)
Are there still any long term plans to centralise all BA destinations from T5? I thought this was already in place, except for the ex-BMI operations... If its a case of there is not enough room at the inn, at T5, it is interesting how they found space for IB to operate its routes from there.
Is there room for additional gates and check in space to be built at T5?
If this is not the case, will BA centralise all their non T5 ops, from just another single terminal, and if so which one would this most likely be? Is there space from a single terminal to operate all the routes from?
Also are there plans to centralise atleast flights to the same destination from the same terminal in the long-run? As you have destinations like Aberdeen, Edinburgh, Manchester, Moscow and to Saudia Arabia, from both terminals 1 and 5.
Sorry so many questions...
List of destinations from T3
Bangkok
Bucharest
Budapest
Gibraltar
Helsinki
Larnaca
Lisbon
Prague
Singapore
Sydney
Vienna