Shrub ID Possibly Needed

I bought this shrub off a sale bed at a farm shop in Cheshire last week for £1, its very healthy and in perfect condition and shape, however there was no label. I love purple leaved shrubs so that's why I bought it, it looks for all the world like a Physocarpus Diablo, which I bought off our market a couple of weeks ago; however the leaves are much smaller (hawthorn leaf size) and much, much more numerous, apart from that though they are more or less identical in shape and colour, both being green on the underside, any ideas?

Thanks in advance

 

looks to me like a variety of Physocarpus opulifolius.

 

There appear to be several rather similar Physocarpus.
Physocarpus opulifolius Diabolo

Physocarpus Diable D'Or./syn Coppertina.

Physocarpus opulifolius Seward/ syn P.O. Summer Wine.

Physocarpus opulifolius Lady in Red.

No idea how you tell one from the other though!

http://www.soltygardencentre.com/assets/images/products/1Diabolo Ninebark.jpg

http://www.google.co.uk/search?hl=en&cp=19&gs_id=24&xhr=t&q=physocarpus+diable+d'or&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&biw=768&bih=388&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=zbwNUJSUFISa0QWDoLHpCg

http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/plant-finder/plant-details/kc/c422/physocarpus-opulifolius-seward-summer-wine.aspx

http://www.google.co.uk/search?q=Ph...g&biw=1184&bih=594&sei=974NUOXxJILX0QXImrnDCg

 

Thanks Silver Surfer