I have just heard from Bexhill station that the only way back to Eastbourne and beyond is to take the train? to Brighton travel to Haywards Heath and change to the Victoria Line train.
This whole thing is getting very confusing, looks like the TV then!!!!
Sounds a bit dodgy. If you can get the shuttle bus back from Amex to Lewes then trains are running back from there to Bexhill. You'd pick up train from London at Lewes.