There are some small groups that train in York, but they don't use these forums. Most of them are also relatively new to parkour as well, and not really in a good position to teach. I think Echo might be the only experienced practitioner who's in York on a permanent basis, and uses this forum. I know a good group that practises freerunning and tricking, and can put you in touch with them if that's more where your interests lie. If it is parkour that your specifically interested in, I will be training in York during the Christmas holidays, and your perfectly welcome to come along.