Suzi
if you are a complete beginner, a good starting place would be on one of the rides organised by Bugeye, look out for them, they usually meet on a sunday at the carpark next to the prince regent hotel in chingford at 10am ish. there is nothing too technical and its a nice ride with friendly folk.
when you are ready to progress try looking at uk bike skills with jedi where a skills session with them is worth every penny.
some people also organise midweek rides at epping.
epping is a little bit boggy still so a riding companion who knows epping would help keep you rolling.
also Heales cycles in hyams park have rides on most sundays into epping for all skill levels.
there is an old saying "no one gets left behind" so as long as you dont mind waiting for the others