It seems that between BA and BAA there is a mighty cock-up waiting to happen.
1.) Because BA have decided to retire her on the Friday of October half-term, historically the busiest travel day of the year. (Remember the times they've had to close T1 due to overcrowding?). But this year, not only will the world and his wife be heading towards LHR, the cousins and grandparents will be as well!
2.) BAA have only suddenly realised that there are a number of people in the UK who actually care that this country's significant contribution to the history of commercial aviation is having its swansong. So they've come up with a half-cocked plan to allocate 1000 viewing seats to lucky members of the public.......as if it's some sort of Ryder Cup final match. So what are the other 249,000 people supposed to do?
I hope the day goes well, as I'm planning to be there. But I'd advise (along with others) to take some sort of concrete ground transport......tube, Heathrow Express etc. Not a car as you'll never get parked and you'll get stuck in traffic.
(Personally, I plan to fly in and fly out.)