Originally Posted by
NWIFlyer
Actually, that brings up a good point - very early morning flights from T5 starting from a central-ish London hotel are an even bigger nightmare because of the additional transfer from T1/2/3 to T5, requiring a walk to the Central Bus Station/Underground area and then either a tube running at 15 minute intervals or a N9 bus with a timetable which is advisory at best.
This is incorrect.
ALL Heathrow Express trains continue on to T5 after stopping at Heathrow Central (T2/T3). Travel time is 15 minutes from Paddington to Heathrow Central, if going on to T5, an additional 6 minutes after the train leaves Heathrow Central.
The Tube does essentially the same, however, the first train from Central London arrives too late for the earliest departures.