Just went into AMD in Woking, Surrey and met the owner of AMD, Simon Howarth.
I was asking about difference between Revo and AMD Stage 1, and he said they are identical apart from the fact that Revo is switchable to stock via a dongle. He also said I could expect around 260bhp!!
The difference in price?
Revo 479 inc VAT plus £180 inc VAT for the dongle.
AMD 349 in VAT, and offered to return it to stock FOC when I come to sell the car! That'll do for me! Booked in.