Horn doesn't work.

I have a Ford Mondeo R reg and my horn doesn't work.Checked horns independantly and they are ok,checked fuses and relays...ok.Need to get this fixed due to MOT being due soon and can't toot !!.PS :The clutch was replaced in June last year and all sorts of lights are blinking now and I am sure it stems from this,but cannot take it to the garage as we were in Devon at the time on Holiday.Hope someone can help me please and thanks in advance.Please don't ask me to buy a new one as I am a pensioner.