Right I have finally proved it is the interface. I have borrowed a known working lead from a friend with fiats, plugged it in, and boom canbus works.
So the interface I bought from ebay (blue and orange about £16) is crap and doesn't work with ELM. Anybody want to know the exact supplier, pm me
So I'm now waiting for a replacement to arrive, I ordered from an ebayer that is also a member here, hopefully that will work I have decribed my problems to him, and he thinks it should. fingers crossed. And the supplier of the non-working interface has also promised a replacement. Should 2 arrive and they both work, I'm happy to resell one on here as know working (But lets see if it arrives first)