The bark is similar to Russian Olive, however RO has fuzzy leaves, while the pictures show very shiney leaves.
I was looking at the lateral in picture 4, and shows similarities to advantageous growth of willow.
If you were able to prune a piece of larger wood, that would really help solve the mystery.
My book resources are limited to trees in Canada, On the Isle of Man, it might be anything. Good luck, I'll keep an eye on here and when you find out, I will be wiser too.
