A Hypericum (St John's Wort) perhaps? Don't know the varity , but someone else will, I'm sure.

I thought that too, but I'm not certain. The leaves don't look quite right.

What about Hypericum Rowallane? If it is a Hypericum, then that's the nearest match to your photos. Can't be certain, though.

Potentilla Goldfinger maybe. Google images for this look similar to your plant.

I've just looked at some other pictures of Hypericum flowers and they look exactly like the one in my garden, so I guess were half way there! Thanks guys.

The leaves are quite wrong for a Potentilla. It's definitely a Hypericum, & the leaves are right for Rowallane.

@Ojibway93 - Hypericum Rowallane looks exactly like it, 99% sure! Many thanks.

Welcome to GoY.