Maudarby,
This is splendid! Thanks so much for unearthing all this extra detail...You've also discovered for me that Margaret PENDRILL (nee ROSS) must have continued having children - daughters - and that with Judith mentioned as J.P.'s "eldest" daughter, something must have happened to the two other daughters who were baptised in 1785 and 1790 in Jamaica, namely Marianne and Mary (so states the IGI, so I suppose I should be cautious); perhaps they stayed in Jamaica...
All those other marriages seem to indicate that the brides all had William Campbell as their grandpa, and therefore their mother would have to be Margaret, who had at least six daughters then.
I've just realised now that I got the info about John PENDRILL marrying an Ann PENNY as his second wife from a 1993 list of PENDRILL descendants, but when I look at a more recent (albeit 1998) entry on the Staffordshire Rootsweb, there is first the contradiction that he and Margaret ROSS had no children, then further down it actually lists 7 children for them:
i) William ob. inf.
ii) Judith Campbell PENDRILL ob. 18-12-1870 married Rev William David LONGLANDS (date given here incorrectly, husband's death as 27-12-1806, as they didn't marry until 1822, as you say!)
Computer misbehaving, will post and continue keith