DEcosse
If it's no Scottish it's CRAP!
Ah, bad luck there - good on you for at least getting into it.
If you prefer not to use butt splices to butcher your OEM harness, you can go one of these routes:
a) Replace the male connector on the new key-switch to match old style - 250 Series Motorsport Connectors - Corsa Technic
b) Replace the female connector on the main harness with the new style directly - 8-Way Kit (get largest terminals and seals)
As mentioned earlier you should definitely look to a headlight-key-switch-bypass mod or it will surely happen again; this is the simplest way to achieve that with a single relay - New member in Japan: 30A fuse blowing (horn, turn signals)
If you prefer not to use butt splices to butcher your OEM harness, you can go one of these routes:
a) Replace the male connector on the new key-switch to match old style - 250 Series Motorsport Connectors - Corsa Technic
b) Replace the female connector on the main harness with the new style directly - 8-Way Kit (get largest terminals and seals)
As mentioned earlier you should definitely look to a headlight-key-switch-bypass mod or it will surely happen again; this is the simplest way to achieve that with a single relay - New member in Japan: 30A fuse blowing (horn, turn signals)