I am replacing an old narrow Miralec shower with a new Triton shower, using their Instatrim, which allows pipework to be routed behind the shower. The old appliance is connected using a soldered tap connector which would be difficult to remove due to tiles etc. I want to use a flexi pipe to join to the new shower but need a fitting to connect to the tap connector. Would a 15mm / 1/2" male iron fitting be suitable for this? I assume if I did use this it would still be sealed using a fibre washer rather than PTFE tape on the threads?