ok. just replaced the whole carburetor with new. Still same problems. In fact even harder to start.
Finally got it running - idle problem might have been due to a loose throttle screw - now adjusted and idles ok but I have to have it at pretty high revs to keep it "idling". Not enough so that the clutch engages though.
That done, I turned to the spark. Just had a look at the plug which is only a couple of weeks old and it's black black black. Maybe from all my turning it over to try to get it started? no idea.
Below is an image of the spark plug. video to follow shortly.
In summary, I'm back to square 1 now. Got a running bike, but with no acceleration...
Next step change the battery? I had just been charging when I took it for testing. Could have been wrong. I'm thinking of biting the bullet and just taking it in to the garage.