Looks like creeping buttercup to me? ( don't know it's proper name)

Looks like one of the perennial geraniums. Good plant with attractive pink or blue flowers in early summer. Will clump up and spread and grow much bigger and keep the weeds down too.

I'm not entirely sure (but I'm certain SOMEONE will be) but that leaf shape suggests Winter Aconite.

Winter Aconite.

Creeping Buttercup is less curvy and more pointed. Perennial Geranium is more hairy and slightly different leaves.

Winter aconite, the leaves, if they flowered, it would have been a few weeks back now.

Definitely Eranthis hyemalis, Winter Aconite. If anyone has it and wants to try growing from seed, then now is the time to open the pods and sow the seeds, even, in fact, especially if they are still green.

Thank you all, starting to look a bit faded and dying now though, does that sound right?

Definitely sound right, Marcus. It would have had yellow flowers in March and now should have five seed pods radiating from each flowering stem. If you didn't notice flowers then it should produce them next year.