Thanks for your responses: you confirmed what I thought :-(
Unfortunately there are no earlier flights from London to Houston and no later flights from Houston to Hayden (execpt for the next day - not desirable...). So London-Houston-Hayden is out :-(

So am looking at flying to Denver instead. Thinking of either flying direct with BA or via Newark/Cleveland/Houston with Continental. So am torn between direct flight with BA in economy or indirect (so longer) flight with CO with the "possibility" of them upgrading aome/all of the segments. Is it worth playing roulette with CO's upgrade policy? Any thoughts?

(Have been to Steamboat 3 times before - really like it there. Going via Denver we are looking at spending a couple of nights at Winter Park on the way up - never been there before).

The US Immigration alert is a real pain. Not sure that a new passport would do anything (the alert and the "false" dates are in their computer system) - wouldn't the new passport still bring up all of my old records and alerts? Certainly , up until now, the incorrect stamp has helped explain the situation to the immigration officers: seeing an entry stamp saying "23 Aug 2002" in June/July this year showed that something was obviously wrong... The officer in Miami, this July, said that he would try to have the alert removed, but I am not holding my breath... :-(

Boo