Ian,
<p style=”text-align: left;”>You say the dynamo is “working well” – was that a bench test? If so, have you checked output, both before and after the regulator, with it running on the car?</p>
If all is well and charging current is getting beyond the regulator, I would suspect a fault in the wiring thereafter.
Relevant wiring diagram can be downloaded from the technical area of the Members Only section of the website. The one for your vehicle is page 12 of the pdf file
Bernie