New electrical fault (lights)

Hello everyone

Happily driving my 12 plate 110 2.2 defender today, with dipped headlights on, and: - the alarm horn(s) started to come on, which took me a few seconds to realise what was happening, and must have alarmed the cyclist I was overtaking at the time. Pulled over and switched off ignition, then restarted - no horn, so no problems i thought, happy days.

Got home and:
- left front sidelight not working
- left tail light not working.
- background dash lights not working (eg lighting up speedo)
- rear fog light not working
- little green dash light (showing headlights are on) not working, but blue headlights dash light working.

Everything else seems OK.

Checked lamps - OK. Checked fuses (visually) 11-20 under the steering wheel - OK.

The trailer 'repeater' green light on the dash comes on very briefly when left or right indicator is used, but maybe this happens normally and I've just not noticed before.

I'm presuming that this has something to do with the wet, but errh help! Any suggestions please?

thanks for any help