After dropping off my bags at the school, I stayed at the Waltham Abbey Marriott. Quite a few other riders stayed there as well, but it's a bit isolated from other amenities.
If you want to stay closer to central London, you can take the rail from Liverpool Street Station to Chingford and then ride ~4.5 miles to the school. There is a closer station, Debden, but you can only take bikes on the Central Line from Leyton station(~7mi outside central London) and north.