Caporegime
ive never heard of shops charging an "admin fee" when using cyclescheme, if any shops do then you should use one of the thousands of others that don't. The only time we ever alter the price of a bike under a bike to work purchase is if the bike is already on sale eg
we are doing 2015 defy 0s at £800 from £1000
if you wanted to buy that bike from us using an £800 c2w voucher we would only get £720 so we charge the customer the £80 difference as you cannot/will not lower the price any more. Almost every shop/website uses the term "cannot be used in conjunction with other offers" this is roughly the same thing.
Plenty of places charge an admin fee. Not the big chains, but many smaller places do.