What is this berry- bearing bush? And are these strawberry plants?

The berries on this bush were red at the start of August and ripened to this dark purple. Can anyone tell me what it is?



I think most of this patch is strawberry plants but I'm not sure. If they are strawberries then I think they're quite a few years old as they don't look like they've been fruiting. If this is the case, is it worth taking cuttings from any runners? Obviously the patch also needs extensive weeding. I'm thinking about digging out the whole area and starting from scratch with it. Any advice?





Sorry about the small images, I don't have enough posts or likes to add a link to the larger images yet

 

The ones in the first picture are those of Hypericum hidcote and are extremely poisonous. Not sure about the other pics, possibly strawberries.

 

In the last pic, I'd be wondering about creeping buttercup. They have similar leaves. Also looks like some ground ivy in there.