All done!
Seems I had a similar problem to Tresco, the orange/green wire underneath the relay holder had become disconnected from pin 1. There isn't a clip in the holder so the wire has to be held in place underneath with a finger when pushing the relay into the holder. A gentle pull on the wire afterwards just to check it is connected to the pin on the relay. Strange that pin 1 doesn't have a wire holder, just the hole. It's the same on another holder I have for the spare wiper relay I carry next to the working one.
More worrying is that my local Morgan dealer said they had checked the wiring and that it was a faulty wiper stalk. They could order one up for me but the car would have to go back in to have it fitted!
Thankyou all for the guidance - as usual the forum members come to the rescue.
