The serrations on the leaves don't look like the usual elm to me - there doesn't appear to be enough of them, and neither does that awesome bark. The leaves have a matt finish, no gloss at all. Actually, the leaves remind me of 'Continental Parsley' leaves (no, I know it isn't that). The bark is quite hard - nothing 'corky' about it at all. Overall, the tree is exceptionally healthy.
Hope I can get a definite ID on this one - even if it does turn out to be a Corky Bark Elm - just so we can put everyone's mind at rest.
The guy that owns this has extremely limited vision due to Type 2 Diabetes and it's very difficult for him to work on his trees - although he sure does try, and he's getting some pretty good results. He wants me to help style this one, but I'd like to know what I'm actually dealing with before I attempt it. Don't get me wrong, I'd love to have this particular tree myself. That bark is incredible. By the way, that trunk is over 50mm across the base.
Solved
By Bodhidharma - Ash Fraxinus Augustifolia