Pruning Prunus

I have three trees, Plum, Damson and Greengage. They are in desperate need of pruning to open them up and the Victoria especially is spreading too wide. According to my book, they should not be prunes over winter for fear of infection but should be pruned in the Spring/Summer when they are growing vigorously. The trouble is, if I do them then (now), I risk losing any of the few fruit they might have set. Is this just a bullet I'm going to have to bite?

My book says that too    .
I’ve not pruned mine for years because of losing some fruit. They really need doing!
I think we’re just going to have to be brave and do it   .

I would leave it until July, A few years back I pruned a Victoria in April and has never fruited since.

Thank you.

I only ever prune stone fruit after I have harvested to avoid silver leaf unless the branches are dead, damaged or diseased.

I have a little plum tree/bushes it’s not fruited yet, it’s about 5ft high and I’ve pruned it most years to make it a tidier shape. I’m guessing that’s the reason. It’s got some fruit on it this year but also some curled new leaf which the ants seem very keen on. I’m wondering if there’s some bug in there.

I have a little plum tree/bushes it’s not fruited yet, it’s about 5ft high and I’ve pruned it most years to make it a tidier shape. I’m guessing that’s the reason. It’s got some fruit on it this year but also some curled new leaf which the ants seem very keen on. I’m wondering if there’s some bug in there.

 
I understand that you need to cover peach trees over winter or they get peach leaf curl. The leaves fall off and that means the fruit can end up small.

I’m not sure we’ve even had a frost yet this winter. A couple of days that came close, but as I’m out walking the dog around 6am I generally see ground frost if we’ve had any.

I have a little plum tree/bushes it’s not fruited yet, it’s about 5ft high and I’ve pruned it most years to make it a tidier shape. I’m guessing that’s the reason. It’s got some fruit on it this year but also some curled new leaf which the ants seem very keen on. I’m wondering if there’s some bug in there.

 
I understand that you need to cover peach trees over winter or they get peach leaf curl. The leaves fall off and that means the fruit can end up small.

That's true for peaches and nectarines, but not plums!
I've dug up nearly all  my peaches and nectarines this year as I can no longer cover them.  Peach "Avalon Pride" seems to be more resistant so I've kept them for a while longer anyway.

I’m not sure we’ve even had a frost yet this winter. A couple of days that came close, but as I’m out walking the dog around 6am I generally see ground frost if we’ve had any.

I could be wrong but I'm pretty sure Peach Leaf Curl comes in rain water. 

@Veggie I don't even know why I wrote about Peach Leaf Curl when we were discussing plums!!