Have noticed that some, not all, pre-1900 births are showing mother's maiden name in the index.
Always were, John Grenham noted last year in a blog and offered an explaination but as they seem random I was thinking more that were perhaps ones that had had user corrections to fornames/surnames suggested by the public and they had had to revisit to correct so had added at same time.
Think they are/were all included from Q1 1899 (not 1900) ie a birth 29 Nov 1898 registered 2 Jan 1899 will have maiden surname but one 30 Nov 1898 registered 10 Dec 1898 will not.
No rolling year and most of the site FAQ's etc are the same with a transfer into a longer mobile portrait format from a PC landscape one to assist one-off phone searches rather than someone spending more extensive time on a PC opening loads of pdf tabs.
Whilst in the search results page they have Mother's Birth Surname: N/R for an 1864 birth when open the Birth record for is 'Null' as in not recorded/untranscribed, null and void, threw me was looking for a mistranscribed Neill on the pdf for a sec.
