This reminds me of Houttuynia cordata Chameleon? but not the usual variagata one. if it is they get lighter in colour the more sun they get.

It's a persicaria. I used to have one called "Devon Bubbles" but lost it. Off to google species.

I think it's Persicaria capitata as the leaves are quite rounded heart shapes. The other possibility is Persicaria microcephala but I think it has longer leaves.
Nice plant. :-)

Thanks a lot, that's really helpful.

You're welcome :-)