From what I understand bitter kit/tin will be ok, but you will need a new yeast sachet.
Dunno about the beer kit enhancer (BKE), but in any event, having just used it to make up a batch and then tried it from primary, I think using 100% spray malt as opposed to BKE is the way forward - the BKE, being a mix of sugar and spray malt, imparts dodgy flavours
