Hi Handaros
The only on line source for Scottish BMD records is
www.scotlandspeople.gov.uk. It is pay to view but costs are reasonable. There are cut offs for viewing images of BMD certificates on line. For marriages this is currently 1933. SP have recently introduced the new extended marriage indexes up to 2006. You can search for the marriage and then order an extract from the certificate on line through SP for £10.
I've had a quick look but cannot easily see the marriage showing on the index with the names you have given.
With birth entries, the cut off for viewing images on line is currently 1908 after which date you have to also order the extract. Looking for Thomas' birth I can only see one, in 1942 and in Fifeshire, but not St Andrews (I haven't viewed the search results).
If this is Thomas' birth entry, it will include date and place of parents' marriage which may help if you are having problems locating their marriage.
Monica
