Wow but time flies! So coming back to my original Gasser, the issue was eventually found to have been a combination of a blocked fuel tap, and a very elusive kill switch cable which had chafed through inside the outer sheath and was making intermittent contact.
Since sorting this out I have had many hours of trouble free riding and absolutely love the bike!
Just got my hands on a 2011 EC300, so I now have two parked next to each other..