Is this a weed? It is quite rampant and is much bigger than a few weeks ago when the photo was taken. It hasn't produced any flowers yet and I don't know whether to keep it or dig it up! There should have been a clematis around that spot but the leaves aren't like a clematis; and a honeysuckle should surely have shown some sign of flowering by now?
the plant in your initial and later pictures with the red stems twining round themselves is Russian vine, Fallopia baldschuanica, http://en.wikipedia.org/wiki/Fallopia_baldschuanica
Also known as Mile-a-minute as it grows very fast and will swamp whatever it can that will support it!
The other plant in your initial picture with the rounded leaves climbing up the wall is a Campanula.
My advice would be to get rid of the Fallopia if you can, there are much more manageable and more attractive climbers out there if you want to mask the wall.
Thank you Jen, you must be right. So it is a cultivated plant - sort of - which I vaguely remember buying. BUT, like Buddlia, it is obviously not a good idea after all, even if bees love it.
It seems an alternative name is Polygonum baldschuanicum - same group of plants as the Japanese knotweed - also a pest.
I can't get rid of the Campanula either, but at least it is smaller doesn't quite swamp everything and looks pretty in the wall. The garden border was full of it when I moved into this house.
Finally managed to dig the thing up the other day in a rare patch of dry weather. Sure enough it was something I innocently bought, probably only about a year ago. The original stake with garden centre tie attached was there under all the greenery. Never again! Hopefully I got all of it; although the roots were impossible to completely dig up - they are like the tentacles of some subterranean monster!