Thanks a million Joe, you've confirmed the stuff I have, and the Dundee connection is very interesting - a different direction for me to follow! Your interest is much appreciated.
The Mavors were all stonemasons, there were loads of them in Dysart and were involved in a lot of the building in the 19th century - I found a website which listed the contractor employed to deepen Dysart harbour in the 1870's as David Mavor & Son. Quite interesting for us as descendants of these builders! I now need to research original George's siblings as I have Mavors which don't seem to belong anywhere - I've a feeling they are George's nieces and nephews. I live in Fife so if and when I can get the time i will visit the library and trawl the OPR's. If you turn up any more info I would be delighted, and thanks once again.
Ruth