Hi,
I have just came across this thread after looking into my own family tree. Well before I was born, my fathers family changed their surname from Caroen, and families being families, the only explanation I knew of was that "it was something to do with a distant uncle or male relative".
I have been able to trace back to a Peter Alphonse Caroen Born 1900 marrying a Mary Jane McIntyre in 1929, Kircaldy. I looked into Peter's birth certificate to expand the family tree further, and noticed that his parents are listed as Jeanie Caroen (Barclay) and John (something beginning with B but is illegible) Caroen who was deceased at the time of this marriage.
Could this John Caroen be the Jean Baptise Caroen who married Jean Barclay in the Dundee area as it would appear he did change his name? I cannot find a death certificate for him, but it would tie in with a previous post that said he died in 1922, therefore deceased at the time of his sons wedding in 1929. On this same certificate, the witness appeared to be a Maria Alfonse Caroen/Brown, possibly a sibling of Peter and daughter of Jean and John?