So here's my temporary solution, giving Cableman a few days breathing space...
Step 1: Drill out old nipple, ensuring that it has a small hole in the back and more space on the front side.
Step 2: Fit nipple over existing cable, small side first.
Step 3: Create End Stop and pull into nipple, causing it to jam into place.
Step 4: Solder into place for further strengthening.
Step 5: Re-fit cable. Play loud music or make sure that it's really windy (as in this case) so that the neighbhours can't hear you swear and shout.
Step 6: Get proper cable from trustworthy suppliers ASAP.