May I ask why you are sure it is a tree, Cinders?
Broad leaves
Have you had a look at this site?
If you scroll down, the first picture of leaves looks very like yours to me.
See what you think though.
Sorry, this is a better site that might help.
Looks like an Hazel .
Laver.
Thank you Mups it is an Elm Wych one not sure. 
Brill. Well done. 
That second wesbite looked pretty good, didn’t it.
Bookmarked them both.