sorry to hear you're faced with having to make these tough choices.
Angelmama - I would get CFC or your GP/FS here to do you up a letter to cover all bases. In all the reading I've done, people are barely ever asked to show one, but it's probably best to have one. Clexane is daily - I have it all the way through as I have a clotting disorder that makes me 8 times more likely to get a clot. It can't hurt with the long haul flight either.