Help identifying tree

Hi,

I'm hoping someone here can help identify a tree I have in my garden. I can't remember it flowering. Here are some pictures.



I love the tangled multi-stem look but ideally want to lower it. It has been kind of pollarded before, the cuts being at the top of the pics to a level about 2 feet above the fence. I can do this again but was worried about timing as leaves look cherry plum type and know these families are susceptible to disease.

Any help would be much appreciated.

Thanks,
Matt