Thanks to all of you for the work, suggestions and detailed information in the replies. Manxians (is that a word?) are clearly a helpful and diligent bunch - I see where I get it from ;0)
Eric - useful to eliminate the Marown families, which leaves the 2 others you suggest.
Jean - yes I think the marriage you identified to Ann Jones is the one (not 100% but there aren't any others which would even seem possible). I do not have any details of his death - where did you find it? It does sound like Callister is the most likely as you both suggest.
Frances - I agree Luciana is unusual name, and it appears elsewhere as Lucinda and Louisa. Probably a result of the handwriting on those early documents. As she is not my direct ancestor it isn't critical for me. As for Thomas profession, the censuses of 41-61 have him as male servant, forgeman stock taker, and Assistant Clerk. And it is intriguing why he would move to Monmouth as its not an obvious destination.