Problem found!!
Removed the battery light cable from the alternator stud and connected it to the alternator pin, and everything works fine! It would seem there is an issue with the alternator stud terminal - spoken to the supplier and waiting to...
Pretty simple check, with volt meter connected at alternator output when engine running you should have 13 to 14v showing.
However as yours is a fitted for radio military model than it would have had a 24v system.
Has it been converted...
Is there a way I can test the alternator, not knowing where the fault is? I did write to the manufacturer but they haven't replied.
The system is at 14.6v but either side of the diode I have 7.13 and 7.2v.
My landy is a 1987 Defender 2.5NA, ex...