Hi Maddys52,
Thanks for the link, that's already extremely helpful.
The baptist chapel marked 'General' is the Old Baptist Chapel, which was already there in the 18th century and so would have been where Richard Grindon was pastor before he moved to Ringstead (which was a Particular Chapel).
Which of course necessarily implies that the chapel marked 'Particular' must be the Bethlehem chapel founded by Thomas the son in the 1830s.
For the record, If I recall rightly, the two congregations joined in the 1930s.