Finally I took the B'Zuki outfit out intending a short run round local roads. Fortunately I started by going to the end of our road then down a local cul de sac with a turning circle at the end. It was awful! As soon as I set off there was a terrible flutter from the bars, getting much worse if either the sidecar or one of the bike wheels hit a bump. I never got out of second gear and was thankful I didn't venture onto the main road. Scared me quite a bit I can tell you. Of course my outfit piloting skills are very rusty!
I've checked tyre pressures at 34 bike front, 38 bike rear and 26 sidecar but not looked at anything else yet. My initial thought is that maybe it's due to the Roadrider front tyre which has quite a round profile. This can easily be changed. Second thought is that aligment is not right although I have checked it carefully. Toe in at 3/4", sidecar wheel lead 10", lean out when I'm on the bike about 1/4" at the tyre. I'll check again. Worst case is just that the bike geometry - trail especially - is just not suitable.