I fitted a new Bosch S4 (4 year warranty) last November in Surrey.
Its not been used for a few weeks and I had a struggle starting it this morning (cold) - in Scotland and had a look under the bonnet this evening. The battery is leaking from both terminals and is covered in a white "fungus" - looks like its been leaking acid on itself and the tray etc and had a wee corrosive piss about the engine bay too.
Anyway its not overcharging (14.5v - I've no way of measuring charging amps). So as its Friday night anyone know who to take it to for a warranty job (like would kwik fit/ halfords warranty a battery sold at the other end of the county).