An update - over all very happy with the bars and having not had a few rides with the 12's as well (mounted to my full sus - Intenser Tracer VP) I definitely prefer the 16's but not sure they would suit the riding in the same way to a hardtail, in that I mean (although this could be many factors) I can get the front end up much easier manualing some as well as doubling up rollers at my local trail centre much easier on the full sus/12's over the hardtail/16's.
I have changed physio (again!) and the new one has made a significant difference. he for one is completely hands off and as I have a chronic problem (ie ongoing for a long time) massage won't work so he had me on some simple "shrug"exercises every other day with weights that made a significant difference in 2 weeks. The opinion being if muscles are weak they will clench and tire quickly (causing aggravation to nerves as well), so strengthen them off the bike so there is more power and endurance so it all takes more/longer to fatigue and become a discomfort. further exercises now added and I recon I'll be hitting the downhill tracks nearby before the summer is out (UK).