Pruning young apple tree

Hello allotmenteers. I have a tree which I planted 2.5 years ago. I read on this website’s jobs list for November that now is the time to prune.  I thought it was a job for mid/ late winter. I am in London. What is actually the best time? If it’s now how much should I take off? Thank you.

Thank you jambop. We haven’t had any sustained cold weather here yet so I will ,eave that job till January/ February. Plenty to be getting on with now!