Thanks for the info. Not happy about 10:30 bus time. That makes for a long wait in the airport and will get us to port way later than I like. Wonder if I can still cancel the transportation and get a car service.
Not sure what the cancellation policy is but it's worth finding out if you're eager to get on the road from Heathrow. We thought about renting a car but decided we'd be too bleary eyed from lack to sleep to drive. Lots of car service companies will take you.