Looks like Circaea lutetiana

Yes - aka Enchanters Nightshade. You need to pull them up but be warned there will be a network of white roots below the surface which is difficult to completely get rid of.

Ah thanks!!! Sounds like a lot of weeding as it's spreading!! At least I know what to do with it now though!!

Circaea may not be for everyone
but in my humble opinion she does have her place.
In my shade, deer and rabbit, black walnut, wildlife/wooland garden, there are spots that i will leave her to do her thing.
Very helpful filling in areas that garlic mustard (Alliaria petiolata) would otherwise take over.

as I mentioned, itâÂÂs not for everyone
but I wanted to leave this info here for folks that may find this plant useful in their situation.

from
http://www.illinoiswildflowers.info/woodland/plants/enchanter_ns.htm:

Faunal Associations: The nectar and pollen of the flowers attract small bees, including Halictid bees (Lasioglossum spp.) and little carpenter bees (Ceratina spp.); they are also visited by Syrphid flies and bee flies (Bombyliidae). The caterpillars of a moth, Mompha terminella (Enchanter's Cosmet), are blotch leaf-miners. Birds and mammals help to distribute the seeds, as the small bur-like fruits can cling to feathers and fur; these fruits can cling to the clothing of humans as well. Deer occasionally browse on the foliage of Enchanter's Nightshade.,\

/end soapbox ; )

Here is a link that might be useful: Connecticut Botanical Society - Enchanters Nightshade

If you have plenty of space and a wild area it is fine. In the average tiny British garden it is a total pain.