I have been tracking the tyres noise on lock as discussed.

On the big Mercedes ML with 4WD etc I have Michelin Latitude all season. In the recent cold snap they have been doing this considerably more. As I reverse onto full lock off the drive it hops as you describe.

On my return with warm tyres I use full lock to come up the drive and with the warm tyres there may be a single small hop but nothing significant.

Coupe has a zero battery.
S2 is SORN so cannot check either of these to match.

Does seem tyre temperature related.

Everyone loves a Morgan. Even me, unless it's broken again.