Hi Coop could just be a dodgy alternator, I just replaced one a few months ago it was an exchange unit, I went through 4 before I got one that worked good, I just remembered when I read pipers post one of the faulty ones I fitted almost stalled the alternator and it ripped the belt to shreds after squealing for a bit, from memory the regulators etc are all contains within the regulator, only other thing is to check the engine earth strap, good luck
Jock