K writes
Stewart Robert Hinsley writes
The number of stamens is wrong for a Lysimachia (compare creeping
jenny and yellow pimpernel) as well.

And the leaves look too fleshy. It may be me misreading the pic, but
the leaves seem to be of similar fleshiness to ivy-leaved toadflax - is
that impression right? - it's certainly more the fleshiness that you'd
associate with some of the saxifrages.

Try Saxifraga cymbalaria - certainly that would tie in with the leaf
similarity to ivy-leaved toadflax (Cymbalaria muralis). Introduced
nursery and garden weed.
--
Kay