The newspaper, The Skegness Standard, 24 December 1941 carried:-
BARKER - NUNDY, at the church of the Sacred Heart, Skegness, on Dec 20th 1941, George A Barker, R.N.V.R. of Southsea, Hants to Edith Nundy, of 'Belgrave' Scarborogh Avenue, Skegness
Whereas the announcement states George A Barker, it does not mention a second name for Edith.
Looking at the 1939 National register for a Nundy family living in Skegness brings up:-
11 Scarborough Avenue, Skegness
Alice N Nundy -- dob 27/12/1898 -- Single -- Apartment House Prop
George A Nundy -- dob 8/7/1890 -- Single -- Joiner
Edith C Nundy Barker -- dob 12/7/1921 -- Single -- General Office Clerk
John J W Nundy -- dob 3/2/1924 -- Single -- Apprentice Garage Mechanic
The fact that Edith's surname was crossed out at a later date and replaced with Barker would be due to her marrying. This could well be the Edith that you are looking for. Her date of birth is almost 8 years after the one that you have for Edith May Nundy.