I've followed the tree identification key on this site, and it shows most of the elements of the Cotoneaster tree apart from it's blossom. The I.D guide says it would have small flat white blossom but the one in my garden has very tiny pink flowers that I didn't even see them until I went to see why bees were so attracted to it this summer.
Could it still be a cotoneaster but a sub-veriety? or possibly the soil acidity effects the colour?
(It has been cut down at some stage and has coppiced if that helps)
It would like to be able to take cuttings or save its seeds so I can grow more of them, because the bees love it .