Phil and Richard - thank you , as always, I'm grateful for your help .
This gives me a lot to go on, I'll take your advice and get a new fusebox and I have a much better understanding of the electrics now. I'm finding out that the previous owners (prior to the rats staking a claim) had made more changes that I initially thought. The wire that leads to the + terminal on the horn is solid black, but I have a much better idea as to where I should be looking.
Cheers,
Rob
