Hi All,
R H
D H for; Robert Hennell I & David Hennell II 1795..1801
(registered Jul 1795) London date letter U for 1795-96
The Lion Passant could be over striking an old maker’s mark of David Hennell I 1739...1755
(registered c1739). Robert and David were perhaps selling off their inheritance under their own name.

Regards,
Oel