Thanks for your response, left accidentally on my posting about Frederick.
Bit annoyed that I didn't think about Wales. All my working life I was in the water industry and well versed in the history of moving labourer (navvies)travelling from one major civil engineering project to another, as scheme progressed.
Charles certainly ended up in Yorkshire as he moved there to work on the major dams - I think, given where he lived, the Derwent Valley Reservoirs, though I think from other clues, he was probably working on Burrator Reservoir as he married nearby in Horrabridge about the time that one was being built.
Checked Wales but didn't find anything for a Charles anywhere there.
Will continue my search from time to time to see is anything new turns up.
Thanks again, David