Hi there, yes it is a double entry type valve ( yorkshire fitting )
I was thinking of trying some microbore pipe if i can`t source the real plastic pipe. I will have to get a small piece and see if it is a tight fit in the valve.
Conversion to a valve at each end will be my last resort :D...
I`ve recently taken off a microbore radiator in my house and it contained a lengyh of plastic pipe which fitted into the inlet side of the isolating valve and i assumed fed the incoming hot water to the far side of the rad. This i imagine helps the flow of the hot water around the rad...