Thomas's mother was Alice Martin. See her will
[Brian's index: RADCLIFFE, Alice 1708-1 And MARTIN E w 0991649]
To sister in law Bahee Martin; nephew John Martin; to her husband [unnamed]; to her brothers John M and Henry Martin; to her mother in law Issable Kneale; to Cath Christian; to Margt Saile; apptd her only son Thomas Radcliffe sole exec; nominated her two brothers supervisors. March 21 1727 Tho. Radcliffe the execr owns to be paid from his father Wm Radcliffe... last will of mother Alice R als Martin.
- Note the mention of her mother-in-law Issable Kneale, who married William's father John Radcliffe in Nov. 1670.

Constance Radcliffe wrote that John & Issabel KNEALE’s son William Radcliffe (c. 1670-1754) was married three times, to Alice Martin (d.1708), Catherine Sayle (d. 1725) and Jane Sumpter als Lace (d. 1754). "Only two children survived from [William’s] three marriages: Thomas the heir (1704-1773), son of William and Alice, and Charles (1720-1747) son of William and Catherine."

This can be confirmed in wills and the Andreas parish register, both of which you need to look at to be certain you have correct information.

Cath Sayle mentioned Thomas the heir as well as her only son in her will:
http://www3.telus.net/lawson/twill/1725_011.html

The William Radcliffe who married Margaret Lawson was from the Llen / Lane / Ballalane [Andreas parish register].

Sue