Thanks for the replies
mickrobbo
vast majority of start delays are due to bad planning from the airline who occupies T5
I think you give the occupant of T5 too much credit. I don't think they do "planning".
Cauatc
Taxi times at LHR vary. 25-30 min seems standard recently, but 8 minutes is the quickest I achieved at LHR. 48 minutes the longest (and that was after 20min start up delays!)