Coming to the end of a long and problematic plumbing refit. The house is old, extended at least 4 times, has been flats, even a rooming house. It is 3 story but with 9 different floor levels which has made pipe routing a nightmare. One last prob is to get a 15mm cold (main) feed to a particular spot (which I have been dreading) but there is actually a redundant (capped) gas feed which goes there and I have double checked that there is no other feed onto it.. Age is unknown but prob 15y, its 15mm not half-inch, it was a job well done and still is. Temptation is to use it for the main. Old solder specs could be an issue but its not a drinking water feed. Somehow though, it just doesn't 'feel' right and I would appreciate your opinion.