Left my bike in for a service yesterday and everything is grand apart from a creaking/scraping noise coming from the rear hub. Said to the mechanic and they've had a look at it, just got a voicemail from them saying the hub is fine but the freehub body is on the way out, they're saying it's going to cost £40 for the part and £20 to fit it. Does that sound about right? I've had a look on Chain Reaction and there's a 105 9spd body for £32 - it's an ultegra hub with a 9spd sora cassette. Better to buy that and have the shop fit that?