There is a reference to Jadwin Dunscombe in Bermuda: There is a Jadwin Dunscombe mentioned in "Association Oath Roles, New York, etc., 1696, in Hamilton, Bermuda, on 7/29/1696." I have unearthed a copy of this on the Internet (www.rootsweb.com/!bmuwgw/oathrolls.html) which gives his name as "Jadwin Downscombe" of Hamilton Tribe. My personal opinion is that the Jadwin in the Oath Rolls is not the Jadwin born in London, but more probably some other later descendant of Thomas and Hannah (Jadwyn) Dunscombe.
Whether this is the same Jadwin baptised 1618 as the son of Thomas and Hannah is not certain. If not he would seem to be a grandson of Thomas and Hannah, though his parent's identity would be a mystery. The fact that he is the only son of Thomas and Hannah to be mentioned in his grandmother Elizabeth (Rodway) Jadwyn's will supports the idea he did not emigrate to Bermuda, at least not by this date.
Deposition by brother Samuel dated Nov. 8, 1705 states Jadwin died without issue (Comp. Vols. 4,3, p. 199 - 200, Bermuda Archives)
The London Merchant Taylor's School Register indicates he was born 2/5/1618 and baptised 1/28/1619, despite the fact that his parent's married 4/12/1618. It's possible this involves some confusion with the years under the Julian as opposed to Gregorian calendar.
Bermuda National Trust notes state a Jadwyn Dunscombe witnessed the will of William Pitt in 1742 on Bermuda. I thin it more likely the Jadwin noted in the 1696 Association Oath Rolls is the same as the one witnessing the 1742 Pit will than that the one in the Oath Rolls is the son of Thomas and Hannah born 1618.