Started a job today in a very old house and have come across what looks to be K type copper. The inner wall of the copper is extremely thick and nothing will take to it other than a transitional coupling which I cant use because it is on the hot and it cannot be guaranteed that it would hold. I have attached a few photos of what i have along with what looks to be adapters that have been used in the past to take it to 22mm. I'm wondering if you can get adapters for it or if i need to start grinding and filing the copper down to try and get a yorky on it. As per there is hardly any space to get the grinder in and dont feel comfortable doing it given the age of the building as there is a lot of old insulation etc that could easily catch fire from sparks. Any help on this matter would be much appreciated, thanks in advance