There looks to be quite a thick stem leading up to some of the flowers, and it looks like it might be a bit flattened? Can you post other pictures showing the whole plant please, and has this always been 'double-flowered' like it seems to be now?

Yes bamboo I'm fairly sure it's always been dble flowered, it was in my garden when I moved in about 5yrs ago. I just posted another photo.

it looks like Saponaria officinalis to me rather than a phlox. also known as bouncing bet as it moves around the garden. Does it have slightly fleshy underground roots? About 4-5ft tall?

Thanks bamboo, i think you're right, I've never had phloxes in my gardens before so I'm not familiar with them. But I'm happy with a soapworth instead, they're often covered in butterflies and other insects and not invasive. At least not in my garden!

I checked out your new photo - agree that its Saponaria officinalis, full name of this variety is S. officinalis 'flore pleno'. Image in the link below, see what you think

http://www.robsplants.com/plants/SaponOffic

you are lucky Resinone as the soapwort has had to be dug up several times from places where it has 'bounced'. it is very good for insects as the flower is quite lax. never noticed its smell before. must go out and have a sniff.

Very lucky if it is not invasive. We spent as much time digging this out in our last place as Ground Elder and Bindweed. A terrible thug it was.

It grows in the gravel around and under my front garden bench, so I'm drenched in the smell when I actually sit down there, which is not very often! I suppose the gravel acts as a bit of a suppressant which is just perfect here. I'll keep it firmly in its place owdboggy!