I'm thinking her Nan may well have died - have found the following death entry:
Mary Violet M Nash born 25/11/1933, died Feb.1985 Basingstoke
(no other Mary V.M.'s born that time just her Nan).
This birth date does tie in with previously mentioned birth entry. Cannot see any marriage entries for a Mary V M to Edwards, Stone, or indeed Nash!
Looks like obtaining her birth certificate is the only way to go here.
Annette