I have 5 Complimentary First Class Upgrade Vouchers for the Gatwick Express and 5 for the Heathrow express that are valid until 30.09.2008. You just need to purchase an Express class ticket before boarding the train.
I won't use them so just PM me if anyone wants them and I will stick them in the post (UK addresses only
) when I am back in the UK next week, first come first served.