Many thanks for everyone's input, comments and interest on my little err... project.
Raven back safe and a short 6 mile test run yesterday. Weather here in Aberdeen UK - awful, hence short ride.
Shifter would not come off the old bars. I tried and failed. The bike shop had to cut the bars.
Looks like some kind of metal fusion has caused the problem.
New set up with the Thorn Mk2 comfort bars.
Feels much wider than the old Humpert bars and gives me a more up-right sitting. Like the 'soft' hand-grips.
I was concerned about being able to fit a mirror but my old one can be strapped around the end bar fine.
A better view of the left side.
And the right
Close up of the new shifter.
I find it more grippy - if that's the term. Easier to twist n shift.
Off topic but...
I took Dan's advice about the curly wrist strap for the Defender key - but still managed to loose it one day in the supermarket - so it now has bells on. A gentle tinkle follows me as I ride.
And finally...
A present from my daughter on my 61st b/day last week.