Hi Adrian and everyone!
I was in the same situation when I replaced the lever for a muscle box some time ago. So, to help you not repeat my mistake:
If you decide to buy a swaging tool and do it yourself, check that the shop and tool manufacturer offer appropriate ferrules for the tool you are buying. The ferrules need to be copper, and need to be thin enough to run throug the sheaves after squeezing.
Still, I think it is much easier to do just the measurements on your own and then order a finished halyard. I ordered mine from:
by filling the form on the website. The details I stated were:
Wire 7 X 19, dia. 3mm, hard eye + soft eye
Length = 5855mm
Length LP = 50mm
and it arrived perfect. I think they even put the spliced rope tail, I probably asked for that via ‘Notes’ but don’t remember 100% any more. Of course measures for your boat would most probably be slightly different.