A note from Chris Heath reads as follows:
There are several Thomas Heaths in the Exeter Heath tree. One is Thomas Heath who was married Mary . . . in ??? They had 5 children, one of whom was a Thomas. He had a brother, Benjamin who became a merchant and fuller in Exeter. He married Elizabeth Kelland. They had 5 children. One was a Thomas again. He was mentioned in his father's will in 1725 when he, Thomas, was still a minor. However, his birth date seems to be unknown although he was baptised on 11th October 1729 at St Leonard's, Exeter. He was a merchant and then an Alderman. He became Sheriff in 1732 and then Mayor in 1738 and 1749. He died on the 5th and buried on the 12th July, 1759. Thomas Heath had three wives: Anne Philip Pyne, m.19th December 1730 but died 29th December 1736. Next was Anne Maria Pyne, m.1737 and buried in St Leonards on 16th February 1754. Finally, there was Ann Gandy who he married on 17th July 1753. She was buried at St Leonard's, Exeter on 9th April 1754. While there were other Thomas Heaths on this tree, I think this is the one that might apply here.
(bookplate list Heath)