I have a Warwickshire Drooper, and it is supposed to have a straight main trunk and then drooping branches.
It was planted in Spring 2012 as a 1 year maiden. I didn't prune it last summer as the top shoot had already been cut at about 5 foot, but in retrospect I think I should have! We staked it quite low as recommended by a friend.
What is has now is some branches at about 2 foot which are drooping onto the ground, and which I think I need to cut off. And then the main stem is bent over from about 3 foot, and not really supporting the weight of the top branches (which are shorter than the ones low down).
If I cut the main stem to 4 foot and take off the lower branches, it would basically have no leaves or branches.
I think it is good to prune plum trees in July so would be really grateful for any advice!
You can see a picture of it here: http://www.anorakgirl.co.uk/img/plumtree.jpg