I found a spare cable in my toolkit, it came in a Lid bike spares box. I offered it up and it was about the right length so I bit the bullet and cut the old one off, slid the new one in and there was about 5cm to spare. I measured the cable and found it was about 170cm so the standard ones should fit ebikes fine.
I’ve got a good cable cutter so when my new pads arrive I can use the old rear cable to replace the front frayed one.
I’ve tried organic pads and semi-sintered, now I’m going for cheap Kevlar pads which are meant to be the best of both worlds.