Yes, hypericum calycinum, but be aware that it can be too successful! Just don't let it spread further than you want it. Beautiful large flowers

Oooh, as someone who's had to spend hours trying to permanently dig out Hypericum calycinum, I hate the thing, but if you can keep it under control, it might do the job. I don't even consider it great ground cover either - it has a tendency to put out runners below ground and pop up several inches away, leaving bare ground in between. It does, though, tolerate shade. The other one which tolerates shade very well is H. androsaemum and its varieties, but its more of a shrub and gets a bit taller, doesn't spread like calycinum.

Thank you both - have now put up a question asking for alternatives - getting great response!