Pruning Plum Trees

Am I too late? I usually prune right after picking but we didn't get any fruit this year (one night the trees had 20-30 plums each, the next morning, nothing  ) so missed the pruning cue. 
It should be warm well into October and maybe later, our first frost was mid-November last year, and only wet - if it ever rains properly again - from early November.
I need to do quite a drastic prune on both trees, removing about a third of the canopy. This will be the final third after the trees were neglected in their formative years by me!
Thanks all

I've no idea about timing - but I'm doing mine at the moment.

Thanks Veggie - I know it is a summer job rather than a winter one, just can't remember how late we can go as it is rather autumnal now!

I do mine up until the end of this month

Did mine last weekend.