TD5 alternator / electrical probs -Can u help?

[steve c]

Evening all,
I have a year 2000 td5 defender with what i thought was a knackered alternator! For about 2 weeks, battery warning light was flashing on and off (occasionally) I realised battery wasnt being charged (voltmeter on battery), checked the obvious, spoke to landrover, they said it was alternator, I bought one, fitted it, then same problem, suggesting that alternator was fine and that some other problem is causing it, the lack of battery warning light is suspicious, no bulbs gone because there are no bulbs, some kind of circuit board with no obvious damage! Can anybody help me please? Ideas, suggestions or facts appreciated,starting to pull my hair out