For £200 the best bet you have is looking for a mint condition 2006 T-Pro with dual magura brakes, I sold mine a while back for £150, there really solid starter bikes and a great platform for progressing, just keep an eye out on here and post up if you have a bike in mind and need any advise, as to wether its a good first bike or not, because there are some bikes to stay wayy clear of, eg. the old missions, which had funny headtube sizes, and some of the older stock montys which used funny sized wheels etc.