The definitive OTP ( Off-The-Peg ) List (<£500 and <£1,000 sections)

i agree you shouldnt buy a bike on its gear ratio but.. i already have chain rings and cogs of that ratio they sell on the otp and if im going to buy a complete i dont want to spend a extra 50 pound on top for a chainset and cog then maybe find out my cranks dont fit or need to buy extra chain links etc..

I am only suggesting chaining the cog, you wouldn't need to change the chainset but you have a point on extra links (if lowering the gearing) unless you find a smaller cheap chainring and could just change that instead.
Reason I pointed it out is that it is unlikely to have the 100% correct gearing for you so changing the gearing on an OTP is a bit of a given.
Unless people just ride what they get?