I apologise for the lack of responses to all the replies, I have been ill for a few days. Robert was indeed noted as born Bontuchel on most census and Jane always Nantglyn. This occupation on the 1901 census was totally different. I have had no success in locating a gravestone for the pair, I think they are buried in Denbigh, but it's just the matter of proving that Robert Roberts who died due to an accident at work is my ancestor. I think a trip to the archives to read the newspapers again will be on the cards.
Thank you for all the responses, they are fascinating to read.
Kind regards
Nerys