We have a flat which was originally plumbed with BS3505 plastic pipes.

I need to re-plumb a section which starts as the old BS3505 pipe and
ends with modern 15mm push fit. The re-plumbing will involve removing
the existing converter from old to new. As the BS3505 bits are glued
(solvent welded) I can't re-use the converter very easily.

So, where can I get some sort of converter to go from the old plastic
pipe to modern sizes? I can't find anything about BS3505 at BES and a
Google Shopping search tells me nothing except that a copy of the
standard will cost me £92! :-)

The old pipe is marked:-

Yorkshire Imperial Polyorcb
BS3505 1/2" CL E

(Not absolutely sure about some of that)

--
Chris Green