Plant ID help please - wildflower/self seeded

[triplechoc]

I have an area in my garden that gets ignored as it’s hidden by a shed; looked behind it the other day and found this beauty.

However, I’m a novice gardener so have no idea what it is! A plant ID app suggested bellflower, but the shape of the flowers is wrong. It’s completely self-seeded into a brick floor.

I’d love to know what it is - assuming it’s not a problem plant I’d like to try transplanting some to somewhere more visible.
Any ideas?!

Campanula?

Yes, campanula, with the heart-shaped serrated leaves. Bell-flower is just another name for it. I don't know what the tall green foliage thing is, though; that looks rather weed-like.

It’s spreads and is quite tenacious

Ah brilliant, thank you!
Agreed most of what has appeared is weeds, and there are a couple of truly enormous thistles, but these were just so pretty I didn’t want to just clear them without finding out a bit more.
It is amazing what nature will do though when left to its own devices - it’s literally the brick base where an old shed was, no soil at all, just dust, yet all these plants have appeared.

The tall green thing is an Epilobium, a willow herb. It’s one of the small flowered ones so not especially interesting.

Campanula possibly poschka….. for the blue. Campanula are united in having their 5 petals fused into a tube at the base, with free lobes at the top, and a rounded bottom giving them a bell- like look, hence the name, campanile being the Italian for bell tower. But the degree of splay of the tube and the lengths of the lobes vary, giving quite a range of flower shapes