Well, got a bit of a dilemma, dropped the bikes of for their service on Wednesday only to find that the shop had not got the tyres in they promised me they would definitely have when I booked it 2 weeks before. Shop guy was rather vague and said he would sort something out (which didn't sound very confidence inspiring at all, as he had used those words two weeks before). Anyway, had a feeling this might never happen, so just to be on the safe side I ordered a pair of CRC (after trying to ring the bike shop to double-check all day, but they were closed), which arrived this morning. Unfortunately this coincided with me getting hold of the bike shop, who by some form of miracle now also had the tyres in. I asked if I could bring mine round and if he could sell his to another customer (they are standard marathons, nothing weird or wonderful), but he refused. Now, is there any point keeping a second set as spares (considering it would cost me almost £7 in postage to return them), or will the rubber have gone funny by the time I will ever need them? Don't know what to do...any suggestions?