Could also try www.vehcilewiringproducts.co.uk
They are better for smaller orders than polevolt, I wouldn't bother with s/h they're cheap enough new, 12v irons are fine, use silver solder instead of the normal(now banned) lead/tin or as it's known 60/40.
I've always got new ones of these as well as adhesive lined heatshrink if needed, earth wires will naturally corrode even when covered in proper insulation, it gets in the open end at the terminal and creeps up over the years, make sure the joints if soldered are heatshrunk afterwards not so much for water resistance but to stop them snapping the fluxes used in the solder cause a brittleness where it ends and the joint becomes very brittle here heatshrink stops the vibration/movement that causes snapped wires.
The best flux to use is pine resin, so if you have any pine trees nearby use the resin it's ace.
tabetha