the engine warning symbol on the wife's fabia 1.4 mpi occasionally shows, usually after the car hasnt been used for a few days and then clears itself the next day. Anyone had this problem? the handbbok says engine electrics/ exhaust system fault. I was wondering if there was water in the exhaust system , whether this would cause the problem? The car only goes 2 -3 miles per day maximum.

Doing such short journeys will knacker the car. Try taking it our for a motorway run to clear things out and get things properly to temperature and see if this improves things.