Solved this vibration thing at last !
As with all good problems, a bit of accidental helped the diagnosis.
I thought the vibration was from the left front wheel or defo the gearbox side.
Noticed the n/s front tyre was down, so pumped it up and made sure all pressures identical.
Vibration much improved so today changed the n/s driveshaft with another good one.
No real play in the one I took off but problem solved.
Thanks for the suggestions, the fact that the shaft had no discernible play almost made me discount it, glad I didn't.
Also replaced the 12 month old wishbones as the front bushes had already pulled away from the metal case - am in 'negotiations' with supplier with photos.