Unknown tree not well

[Krupion]

I'm new to this forum, hello to all !

We had a tree in out garden, an nice ornamental one that flowers once a year for some 40 years now..

Just now, in spring its leaves are rusted and shrunk on all branches although some new shoots can also be seen in one or two places..

1. what tree is it ?...never been able to ascertain

2. is it dying or will it survive whatever it makes it sick ?

Two simple questions yet I have not been able to find anyone on the whole Internet who can answer these without charging £200 or more..

Would be grateful for any help, thank you

[Stere]

Looks like its under another big tree might be why its sparse doesn't like the shade.

 

Cherry plum?

 

Any blossom?

Edited May 9 by Stere