I recently removed the cistern in my downstairs loo as it was approx 30 years old. Unfortunately it was only when I cut into the painted pipe supplying water to the toilet that I discovered it wasn't standard 15mm metal pipe, but a grey plastic pipe, with external diameter of approx 17mm. I have been to several plumbing shops, and no-one seems to have a connection for me to fit on the pipe to either convert to standard 15mm, or to cap it off permanently.
The same type of pipe feeds the cold water in the basin, but some time in the past someone put a T joint (also plastic) in this pipe and used what looks like epoxy cement to plumb in a piece of 15mm copper pipe, which goes through the wall to the outside tap. Clearly, since it has been done in the past, it must be able to be replicated - but I've had 2 plumbers out to look at it and neither seems willing or able to tackle it!
Any advice would be much appreciated.