Personally I would nip up B&Q before they shut and get a crappy crimp kit, if you are not technically minded, (Red, blue, yellow crimps + crappy tool/stripper)+roll of insulating tape.
Or local car spares shop.
Cut the damaged bit out. Strip the outer 2" each side.
Then strip the inners with 1/4" approx (5mm) and rejoin with red crimps.
If you have a soldering iron you dont even need the crimps.
Strip inners 10mm. Twist or hook, then solder.
Don't mess up polarity.
Remember this is temporary. Don't strain the joints.
Insulate as required. Low voltage side, no danger of shock.