A little update...
Was driving to work this morning and the engine and radio started cutting out for about a second at a time then spring back into life.
Carried on and eventually there was a huge plume of smoke in the car coming from the fusebox area!!
Pulled over and let the smoke clear and could see a brown (earth??) wire had burnt away from the plug.
Car started fine fine afterwards and oddest of all the horn now works as normal??!!
Everything else electrical also seem to work so im stumped as to what happend.
What do I do now as im sure the car didnt decide to fix itself?