@James_S - The Wednesday North London Hills ride is about 35 miles at an average of 16 MPH. It is considered a training ride so the flat and downhill parts of the route can get quite spirited at times. If necessary we regroup at the top of hills. There are a few bailout points to return to London if you determine the pace is to quick.
The Thursday evening ride is a similar distance and speed with a lot less hills.