The General Register Office (GRO) has extended their search form for births so that you can now include the mother’s maiden name. Applies to records pre-1915.
You need to register with them in order to use the search facility. It is a cumbersome registration process; and the search process is equally cumbersome. You can only search in five-year blocks AND you have to give the gender of the child.
Web site address is: https://www.gro.gov.uk/gro/content/certificates/Login.asp
From 2020 the mother’s maiden name is also available at FindMyPast, and is shown in the transcript option.
Their Web site address is: https://www.findmypast.co.uk/