There was, surpringly, logic in my choice of bike and tyre - although it was probably flawed. At the time I was looking to loose some serious weight, but didnt have the time to exercise enough so commuting on a bike with mountain tyres used more energy than road tyres. It also allowed me to investigate moutain biking! I dont think I'll be pursuing that. (I managed to knock 7 stone off in 6 months though!)
Thanks for the recommendation, Im going to have a nosy round a few places, but it would help if I had a least a vague idea of what I was looking for. Will visit that site.
Cheers