| Well, it depends how confident you feel - I would get stuck in, but then I reckon I know what I'm doing, others may of course disagree!!!
It certainly can't hurt to have a good look around, electrics aren't magic - there must be a short somewhere - you just have to find it!
as Weeksy said any mods or repairs that may have been done are prime suspects.
Try to follow all the cable runs and look carefully for any wear marks or pinching.
Has the brake light cable got trapped where it goes up into the seat unit for eg.
Failing that some simple fault finding should be possible - get some more 7.5a fuses and try disconnecting the brake lights / horn and see if it still blows the fuse.
Does the fuse blow immediatly or only when you put on the brakes for eg. It is possible for bulbs to go short circuit so it may be as simple as that.
Good luck, let us know how you get on
D | 
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