sreten

Hi,

There is no B-tension adjustment, its very basic, OEM stuff.

However I loosened everything off - wheel nut - and the
derailleur retaining nut and bush/nut - and realised there
was some wiggle room of the derailleur across the axle.

Setting the derailleur bracket more anti-clockwise has
cured the problem - so I assume it is not normal.
I didn't put it back properly changing the tyre.
(But I think it was like that beforehand.)

(The derailleur is clamped by the wheelnut. The
dropouts are near horizontal - presumably for
single speed/IGH versions - and the derailleur
has a bolt and lipped bush/nut that fits into
the dropouts behind the main rear axle.
I don't know what mounting system that is.)

rgds, sreten.

The penny dropped what to try after posting.