Creating this post as a just-in-case if things don't turn out right.
The car exhaust was brand new, the seller seems to sell a lot of them. It came, we took off the old exhaust (at the cost of my arm dislocating! ). Then it became apparent that the new exhaust didn't fit on to the manifold, I took many pictures with proof, also of the mountings in the wrong place.
The seller first told me to bodge it to make it fit, but eventually agreed to a refund, and that he would arrange for APC to collect it. Seemed genuine enough.
They collected it Friday, but now the seller doesn't respond to any messages.
It could be that they haven't gotten around to opening the box yet to inspect before issuing a refund, but I'm getting worried as the response time was very fast up until now.
I can't open a case with eBay as that functionality no longer exists with them, I merely have to request a return and post it back, however I cannot do this since it's already been collected.