@Cv6benplus thanks, pal - would you be willing to sell the wiring and yellow connector block? if so drop me a PM.

I did think as much.
Yes happy for you snip this wire at the buckle end and the other cable with the yellow connector block. That's exactly what I need.
Why on earth would anyone faff about snipping and soldering, with the inherent problems that could bring, when you can simply take the whole tensioner and buckle assembly, complete with the yellow plug, and swap the whole thing over, maintaining proper electrical integrity. It is probably also quicker and simpler to do. One torx bolt!I did think as much.
I can snip them off and they should be ok soldered with heat shrink.
I'm loathed to try and disassemble the clasp it goes into.