Thank you David, Kay and Brentor Boy. I thought you might like to know the outcome of your help so far.
The John, son of John Balls of Great Finborough, baptised at Buxhall 16 Feb 1752 gave the connection needed between Buxhall and Great Finborough and gave credence to the likelihood that the earlier baptism on 30 July 1749 and burial on 3 Sep 1749, both at Buxhall, of John, son of John & Elizabeth Balls, belonged to the same family.
Consequently, I looked for and found the marriage of John Balls and Elizabeth Osborne on 17 Jan 1748 in Buxhall. This fits time-wise with the birth of their first son. Rather strangely, FS has a second entry for this marriage on 11 Jan 1749. Presumably a transcription error?
I found the death of John Balls on 16 Oct 1794 in Great Finborough. He was aged 69, so born about 1725. Elizabeth Osbourne, daughter of Antony Osbourne, was baptised on 7 Nov 1725 in Buxhall. I still need to find her mother and her death as well as John's parents.
FS has a burial on 28 Mar 1757 in Great Finborough of Thomas Balls, son of John & Elizabeth, and a baptism, also in Great Finborough, on 9 Jan 1758 of another Thomas Balls, son of John & Elizabeth. These two children seem to be John's siblings. Could anyone find the baptism of the older Thomas Balls in either Buxhall or more likely Great Finborough before Mar 1757 please? There is a Suffolk burial on 28 May 1758 of Thomas Balls, son of John & Elizabeth, which might apply to the younger boy if it could be narrowed down to Great Finborough.
In addition, FS has a possible sister, a Mary Balls, daughter of John and Elizabeth, baptised 24 Nov 1754 in Suffolk, but doesn't specify whereabouts. Is it possible to locate this baptism?
Any help to fill in the gaps would be very much appreciated. Thank you.