Can anyone tell me what this plant is called?

It looks like Erisymum Bowles Mauve to me.

see
http://www.bbc.co.uk/gardening/plants/plant_finder/plant_pages/11278.shtml

i agree with joh

Perennial Wallflower, look at my pics of mine

Brilliant - thanks for your help - I do love this site, Everyone is so friendly and helpful

I have one too. You can expect it to make much growth this season. They big up fast towards their full size. Often referred to as a short lived perennial. Great for insects, bees. I keep mine trimmed and manacured with snippers, but you can let it grow looser.

I too Find them not very long livers, but I take heeled soft wood cuttings in late Spring or Summer, to ensure I always have a youngster about!

can you tell me what are heeled soft wood cuttings are! thanks

Look for a non flowering shoot, peel it back from the main plant it should come away with a 'heel' if you then plant that in a pot it will root, or i have even rooted them in a glass of water!

I will give that a go, thanks