Just to give a balance to the story, I landed Heathrow on Wednesday night 20.30 and was a touch concerned from all the reports I wouldnt be able to catch the last available tube (departing 22.09) to connect with the Leeds train.
I actually cleared Immigration, baggage and customs by 20.50.....and caught the 21.09 so plenty of time.
Obviously a UK passport holder but somethings arent always as they are reported.