If I had smaller hands I might have been able to do it without removing the dash, but I couldn't get in there with the dash on.
I took it all off again yesterday. Swapping the working light & wire loom from the left didn't work on the right. The right side worked on the left though, so I started retracing the indicator wiring across the front of the bike and to the big wiring harness on the left side. After cleaning all the connections I put it back together and lo, the indicators all work.
On the upside I've got a couple of spare bulbs now
If Connies sit in a field for a while, the first thing you want to do it clean all the wiring harnesses I suppose.
I also bled the front brakes which feel much tighter now.
Thanks for the suggestions.