"Mizter T" wrote

That said, I imagine that however good the information given at the
Heathrow tube stations, there'll still be a fair number of air arrivees
getting as far as Osterley on the tube before then finding themselves and
their baggage on the all-stations bustitution service A from Osterley,
which runs to Turnham Green (thence District line to get further east into
town).

They've thought of this. Replacement bus service B (eastbound) from
Terminals 1&3 to Hammersmith will call at Osterley, so any passengers who
join the Piccadilly Line at Heathrow won't have to endure the all-stations
bus at Osterley.

Peter