Another tip - just because mother's maiden name isn't recorded, doesn't mean it isn't on the certificate. I ordered one which arrived yesterday. It's from the third quarter of 1837, so obviously early days of civil registration. Indexed as FRAZER, Frances Elizabeth, mother's maiden name is a dash.
Here's the info on the PDF:
Name: Frances Elizabeth
Sex: Female
Name and surname of father: William Frazer
Name and maiden surname of mother: Mary Nind
Informant: Mary Frazer, mother, Evesham
So it looks like the mother's maiden name is there, but maybe because it doesn't say "Mary Frazer formerly Nind" it wasn't indexed, but it's easy to work out that it's her maiden name and she is married to William Frazer.