Thanks for the advice I did check the dynamo was positive earth ,during my tests with the bike running but not showing any charge on the ammeter and with a volt meter accross the battery it showed just over 6 voltsbut did not change at all when bike revved up ,I removed the spring clip and cover from the regulator and put mild pressure on one of the moveable points spring plate it seemed to make contact and ithe ammeter jumped over to show a charge the voltmeter also showed it moving to 6.5 volts plus,I took my finger off the points plate and within a couple of seconds it clicked out and the ammeter returned to show no charge,no matter what I did it would only click in by putting finger pressure on the moving plate and then click out,when I had the magneto completely refurbished the same company stripped and checked the dynamo and said it was fine and showing a good output,so from all this I have assumed the regulator has reached the end of its life that is why I have ordered a replacement
Regards. Colin