Thank you Col for replying.
Here's what I have for the Anderson baptisms.
John (my ancestor) bapt. 22/3/1772 son of John and Agnis (Foster), witnesses Richard and James Anderson
Margaret bapt. 47/7/1773 (MMN Forrester), witnesses James and Richard Anderson
James bapt. 20/8/1775 (MMN Foster), witnesses Richard and James Anderson
Alexander bapt. 16/5/1777 (MMN Foster), witnesses Richard and James Anderson
Robert bapt. 22/8/1779 (MMN Foster), witnesses Richard and James Anderson
And now here's a real fly in the works.
I also have an earlier baptism.
Richard Anderson bapt. 7/1/1770, parents
Richard Anderson and Agnis
Forrester

I can find no record for a Richard which could fit, either. This Richard would likely be a brother or the father of John. The more I look at this, the more confused I get!