Ooop forgive me I meant Wembley of course. Having recently been to the Millenium stadium to watch Wales beat England (
) you can see that stadium made far more impression on me!!
As to Gatwick it might be a good idea but for the 24 hour notice, strick slot times and an asking price of well over £150 at non peak times.
I have never considered Redhill - I suppose it might be worth a try but I have a feeling none of the fast trains stop there. It may not be all that quick getting to the station either.
I always think that Biggin should be a good bet, but it is sadly let down by the awful rail links into town.