Thanks for all your responses and suggestions, I had a call from the dealership today and they believe that they have found the cause.....the timing belt has slipped a cog causing the petrol/air mixture not to ignite completely. The cylinders are only firing on every other revolution.
The solution is to fit a new belt and then adjust the timing accordingly
This is evidently a new problem to both Morgan and the dealership and I will keep you all updated as to progress
Thanks again
Philip
