Hi Paul,
From the snippets of information that I've read over the years, the Adams workshops were a single business only. Grimwade suggests that SA I 'retired about 1790', but this is incorrect as an Old Bailey trial reveals he was very much still in charge of the business in 1798, see:
http://www.oldbaileyonline.org/browse.j ... 7980214-58SA I died 1802/3 (see:
viewtopic.php?f=74&t=32565&p=81936)and no further marks were registered to the business for some ten years, so these marks were really those of the business and not to much attribution should be paid to whether they belong to SA I or SA II.
Trev.