Looks like it'll be most cost effective to purchase all the required components separately. Only thing I'll need to figure out is how long I need the electrical wires to be - I'd be going for the D-Fly as well which I believe adds an extra wire.

Since my LBS would be doing the labour, I'll obviously take them the list of everything and see if they'd be willing to compete (or at least come close) to the online UK shops.