Think I may have found a service record for William Welham having served in the 12th Regiment Foot from 1808 until 1823.
Cannot find any William Welham/variants in Suffolk (or anywhere else) who was a Builder or indeed anything else connecting to such a profession.
However, the army service record whilst probably being the right man doesn't help much as his given birthplace does not appear to exist.
William Welham is shown as born circa 1787 and enlisted 23/8/1808 in Chatham, Kent. He was discharged 25/11/1823 due to 'Hepatic obstructions and general debility' - surgeons report states completely worn out originating by servitude in India. He was 5'8", brown hair, grey eyes.
The interesting bit is that his occupation is given as 'Brickmaker'.
However, he is shown as having been born at Rigney, near the parish of Rigney, Suffolk. Only problem is there is no such place as Rigney (I live in Suffolk) and, as far as I can tell, there never was any such place in Suffolk (or indeed, anywhere else). The word 'Rigney' has been repeated and the writing is quite clear.
Annette