Possibly a variety of Spirea?
I was thinking Spirea also, but it should have at least half day sun.
search Goldflame Spirea.
Thanks ladies. I think you’re exactly right! Have did some googling, and May bush is Spiraea cantoniensis, whereas 'Gold Flame' is Spiraea japonica. Perhaps why it didn't immediately look like a May bush to me. It was very lovely, a real pop of freshness in the shade of a tree.Thanks for taking the time to help me out.Best wishes, Ros