I’m now thankfully back on the air, I attached the wire to the new potted N-type balun using ring crimp connectors, but this time rather than Silkaflex or solder I’ve used some Araldite in the connectors and self amalgamating tape around them to try to avoid water and air getting to the connection. I’m not sure that this will work any better but worth a try, I may need to source some new wire with less of a tendency to corrode for next time.
I also took the opportunity to slacken the wire to get the balun as high as possible before clipping it back on to the gutter. I fold the ends so can afford to lose a little bit when I add new connectors, but it does get more difficult each time…
I’ve checked the SWR readout and am happy with what I see.