My (slightly older) kids enjoy Ribble Valley Juniors. It is usually a Saturday morning kids & parents ride from 10am on cycle tracks in Preston area rather than an "around the cones" skills session like Hotwheels.
All the local clubs (RVJ, Hotwheels, Red Rose etc) come together for summer Tuesday night training 6-7 pm at Preston Uni Sports arena - I think it goes on until September so you could get a few weeks doing that and a chance to speak to people from all the clubs in one place. They run groups for 3 skill levels so yours would be fine in with the little ones doing cones, slaloms etc.
The Pendle club over at Colne is also very popular - think they just opened a new tarmac road track.