Well unfortunately it has been confirmed. The problem is somewhere internal to the gearbox, probably in the selector mechanism. This means an engine and gearbox removal so no Morgan for at least a month
The bad luck is that it had to happen to me, a long way from the supplier and in the month when the only dealer within a reasonable distance is closed for the summer break.
The good luck is that it happened only 20km from home and not in the middle of Sicily last month.
Vitesse have been incredibly helpful with response to emails in a timely manner, advice, detailed instructions, and photos. In over 6,000 Mazda gearboxes supplied they have never had a problem with the gearboxes or the selector mechanism and this has made remote diagnosis difficult. In this day and age their service has been a breath of fresh air, and one must bear in mind that I am not their direct customer but removed by 2 degrees(Morgan and the dealer). I only wish all businesses were so responsive.