Andrew Hargreaves wrote in message . ..
I would now like
to replace it with some sort of small tree.

Hello Andrew
Mr T-marsh recommends crabapple trees for small gardens as they have
good blossom, fruits and a nice skeletal shape in winter. I'd plant
one in my tiny garden myself were it not for the ancient lilac which
currently dominates and which I hope will soon die (flowers all at the
top and too high to prune).
But check what conditions it likes, I'm new to the gardening game,
too.
Good luck
Katharine