Lighting problem / Electrics expert required!

[His Dudeness]

Having looked at the wiring diagram from the downloads section (http://foc-u.co.uk/index.php?action=down...ew;down=45), the relays only deal with the high/low beam element.

Given all the faults you have, I would look at the one common thing, the ignition switch cables/connectors.

I don't think it can be at the ignition because if it was at the ignition he'd be loosing power to the starter relay and having intermittent starting problems but he doesn't have that so the connection at the ignition must be good because the bike is starting everytime. 

Ok, well the signalling fuse was fine but I changed it anyway, still no change. As the tail lights light up ok when the ignition is switched to park lights I did not think it would be the problem... although even with that fuse out the park lights work. If the only thing they need to work is the fuse and ignition being on it should be simple, but then the brake light is not working either.

I am thinking its got to be one thing that is causing all these issues. as my bike is a daily rider, its not like its stuff that could have built up over time. It had its MOT a couple of weeks ago so the horn and rear lights would have definitely been working then. I am still thinking that it is relay related although I do not get how it could be effecting the rear lights or the horn unless there is some sort of rerturn feed via one of the relays.

I have spoken to an electrics guy at work and he does not think the relays are at fault as they only control the headlights. With the list of things not working he thinks it is more likely there is a major wire in the loom somewhere that supplies all the things that are not working which is not connecting as it should.
This is fun

The park circuit and the ON circuit are completely different so the tail light coming on when the key is in park doesn't rule out a problem on that signaling fuse circuit. When the key is in park power goes from the battery to the ignition then straight to the tail light.

Whereas when the key is in the ON position power goes from the battery to the ignition, then from the ignition it goes to the fuses including the signaling fuse, then from the signaling fuse it goes to the switch on the handlebar, then from the switch it goes back to the ignition, then from the ignition it goes to the tail light. So the park and ON circuit are totally different.

You've proved the signaling fuse connection is good but I don't think you've proved that there's power at the fuse. Have you got a multimeter or a test light and we can check for power at the fuse and then at each point along the circuit after the fuse?