One of the bass drivers had become weak at low volume but as the impedance was ok I thought I'd take a look at the crossover and it was no surprise to find a burnt-out tail from the inductor. The damage appeared to go into the coil a little way so I unwound it a couple of turns until the wire was sound and cut it at that point. I measured the length of the damaged piece and rummaged through a box of cables (like you do;-) and found a suitable replacement. It had to be cut to the exact length ( + connection overlap), cleaned, tips tinned with lead solder and varnished for insulation. I soldered the ends together, varnished over the repair and re-wound it onto the coil.
I reloaded the drivers and crossover into the cab and fired them up - hey presto - perfect.
The cabinets just needed a little TLC.