Welcome to the madhouse!!
I used B&C Express (google them). Their website is extensive. Basically, I chose a sprocket & chain set that I thought was about right, then phoned them explaining "This is the set I was looking at, but I want to change the rear sprocket to 46teeth instead of 44."
The nice lady on the phone tapped away into the computer for a second, "no problem we can do that for you, it'll cost..." (I think it was £104 + P&P).
Give them a call, fantastic service & product knowledge. Mention you were forwarded from this forum too.. can't remember if they do a discount, but worth asking.
