How do I find twins in the England and Wales civil registrations?
In one of my workshops, I was given some information about a couple in the UK who had identical twin daughters. Although I knew their names, the surname was very common (Brown). Unfortunately, the relative did not know the registration district, or the year, or the quarter of the year that their births were registered. They knew the mother's maiden name but their births would have preceded the date at which maiden names were made visible in the birth index. They did not know the father's given name at all.
None of the search engines I regularly use (FreeBMD, findmypast, Ancestry, FamilySearch) seem to offer a way of finding two names that happen to fall in the same yearly quarter in the same registration district (other than a marriage of course).
Although not a solution, I looked in each census for the named pair since some census search engines (e.g. findmypast) allow you to find person-A where person-B is in the same household. However, this presumes that both twins had survived long enough for them to have appeared side-by-side in a census.
As it happens, I could not identify the twins I had been told about.