Mystery fruit tree

We had 6 fruit trees planted our allotment last winter. 3 x apple (James Grieve, Discovery and an unknown variety), one plum (Victoria) and one pear (Beurre) but we have a mystery tree!

Now it's winter and I'm wondering whether I should treat it as an apple/pear and prune over winter or a stone fruit and prune early spring.

I've included pictures of the other trees in case the growth habit gives people ideas about its identity. It has lots of buds but both the plum and the pear do.    Unfortunately I didn't think to take pictures of the leaves and I don't remember any blossom-my focus was to keep the poorly planted trees alive!!

Any thoughts on the best course of action?

Can you do a close-up of the mystery tree - does it have spurs which might help distinguish it?

Will do when I next go down whenever that might be. Thank you!

I might be tempted to cut off anything damaged

My first thought was a cherry tree as well.

I've never heard of stone fruits. I need to go investigate this now on Google.

Edit: Okay I know what stone fruits are, basically anything with a pit. Don't think I've ever heard anyone in America refer to them as that before.

Many apples and pears grow off spurs but I don't think stone fruits do? (Others, please do contradict me if this isn't right).

Can you do a close-up of the mystery tree - does it have spurs which might help distinguish it?

I've finally been down to the plot and here are 2 close up photos. Google suggests that these are spurs, especially clear in the first photo so I'm thinking apple or pear...