Cut back 180mm (seven inches) of the outer cotton covering, along with the factory fitted heat shrink, to find new undamaged fresh wires. As you cut back you will need to reapply new heat shrink tube to make a smart job. (Black insulation tape if available)

Reassemble in reverse and order. Put on the wire end ferrules if you have them and connect all wires into connector block as they were, and water tube having cut back as required, refit small hose clamp.