battery depends on engine size, u get diff ones for 1.1, 1.4, 1.6 etc. if you find the new battery runs flat again then the alternators gone... i build alternators in work and if a garage sais u need to pay 200+ for a new one their full crap, all youl have to change in it is the regulator (free in my case) but 80 quid tops new! easily done, 3 screws and 2 nuts. as long as the rectifier has no burnt out capacitors the rest will be sound. u can change this without removing alternator from car btw with a few tools.. dw about tension on these nuts and screws... as long as their up tight itl do...jus disconnect battery and loom going to alternator.