As Heathrow has been on 09's for quite a few weeks it is busy round the Southern T5 taxiways. Everytime I have been out there there is a BA Airbus, or two, queuing at the far taxiway by stands 525/526 and then also usually something else sitting on the taxiways between T5A & T5B.
I would imagine when the rest of BA's operation comes across to T5 it will be even busier down there when LHR is using the 09's.