I think the Will on National Archives might be useful and interesting if indeed he was the one who married the Widow Elizabeth CARD.

Wikipedia

http://en.wikipedia.org/wiki/Croft-Y-Bwla

'Built in 1830 for Thomas DYKE a Monmouth Grocer'

As mentioned in earlier message - The National Archives have a number of 'hits' with Thomas DYKE, Monmouth

inc : 7 April 1823

Surrender of terms to merge in inheritance, and assignment of terms to attend inheritance

Robert JACKMAN of Coleford
Thomas DYKE of Monmouth
Elmes STEEL of Coleford
George & Ann DREW, and John BINGHAM
John TROTTER of Coleford
John LEWIS of hundred of St Briavels
William MORGAN of hundred of St Briavels, coalminer

Surrender from DYKE and STEEL to LEWIS

Assingment from JACKMAN to MORGAN