Originally Posted by
gaume
It's a 7:55 am weekday flight, so from what I gather we're supposed to be at T1 about 5:55 am, hence the reluctance to be away from LHR, even at Paddington and it seems those buses from the perimeter hotels are tricky at that hour.
I think you'll have more public buses from those hotels on Bath road to Heathrow Central (T1/3) than trains from T4 or T5.
If you don't want to take the bus in the morning, ask the hotel to book a car. From the Holiday Inn Ariel for instances it costs 10£. (From the HI Heathrow it's probably the same price.)
Keep in mind that from the Hilton to the train station in T4 is also quiet a walk (you should count at least 10 minutes for that in your planning).