Thanks Ciderdrinker and Tickettyboo. Even though the age is couple of years out, as is the Cardiff record, the inclusion of his full name on the burial record is quite persuasive.
I had always wondered how his widow, whose family connections were all in the West Country and Wales, had been motivated to move to London - I had assumed after his death if it had been in Cardiff - together with three small children. It now appears that JMW moved them, which makes much more sense. He was a baker and confectioner and would presumably not have found it too difficult to find employment.
A particular thank you to you, Ciderdrinker, for alerting me to Deceased on Line. I had not come across it before.