Hi Kerry, you are right that there appears to be another marriage on familysearch.org (parish register extract) for George Tustins and Susanna Warr 21 Apr 1806 St Philips, Birmingham, interesting. Have you looked at the possibility that George was born c 1767 rather than 1787 and had married before Susanna. Also I wonder if there is a link to the George who married Ann Warr in 1795. Do you have a death / burial record for George who was born Butlers Marston?
Shirl