This reply is to both Frances and David, who I thank most sincerely for their prompt replies.
Another researcher gave me information about Robert back in the 1980s based on what his grandmother told him about his ancestors, the principal parts being that Robert was a Captain, and was lost at sea. David has pointed out to me that clearly he was not a captain, but a steward, so one part of the story is prone to fantasy.
I have in my possession a copy of the death certificate of my great great great grandmother, Catherine Hooper, formerly Clucas, and nee O'Brien. Her certificate states that she married Robert Clucas late 1841, and remarried James Hooper early in 1854. Robert was then deceased and I have been told that he died at sea. So far this fits in with what David has told me.
In regards to Clucas v Lucas. My surname itself is testament to what can happen with names. The common spelling of 'Collins' has on many occasions been placed in documentation instead of 'Collin' by those who assume the spelling is not correct. I believe that this is the case of our Robert. 'Lucas' is far more prevalent than 'Clucas'. He was born a Clucas, was a Clucas on the "Adam Lodge", has a typo in the marriage certificate of 'Lucas', and is marked as 'Lucas' on the brig "Gazelle". Another document spells it as 'Clucus'.
To some, it may seem a bit of a stretch, but I am confident that this all fits in nicely for me, certainly far better than what I did have for 30 years. My previous effort always felt like I was trying to put a size 8 foot into a size 7 shoe (it looked OK on the outside, but was uncomfortable on the inside).
I am amazed at just how much detail you guys have access to! Many thanks again for putting me on the right trail. Any other data that you may have would be received with much thanks.
regards
Barry