Hey - Ware Joggers are one option. Garden City Runners also do a beginners class, which is only 2/3 weeks into the start of the current programme.
Your other option would be to follow the NHS' couch to 5 k programme under your own steam. You could do the Panshanger parkrun each Saturday morning, which is a 5k timed event, to measure your progress.
Good luck! Running's an excellent sport for weight loss. I lost 6+ stone in 18 months and ran my fourth marathon earlier this year.