A quick search online shows a marriage in 1897 between one Samuel DIXON and one Mary Maria MABLETHORPE. At first glance this would certainly appear to give me my great grandmother's maiden name, though until I have documentary evidence to support this I will store it in the 'to be checked' tray.

Updates:
2015-03-18 Mablethorpe and Maplethorpe seem to be interchangeable; both being in use in various documents. I eventually settled on Maplethorpe.