Well for the past few weeks my Scangauge has been showing that my battery is approx 12-13.5V when the cars running. After having 2 flats yesterday I decided to go to Halfords to get a test done. Battery percentage showed 75% and alternator showed "too low".

Strangely enough the car starts perfectly fine first thing in the morning but only plays up sometimes throughout the day. Could it be alternator or something else like poor ground e.t.c?

If I do need an alternator does anyone know where would be the best place to get a recon one. Its a 100AMP, well thats what Vauxhall told me