From issue 1610–1619 the gazette has both digit page numbers and digit + alpha page numbers. It appears that the issue numbers did not advance properly in this period so the website has page numbers like '1.a' and '3.a.a' plus the usual digit page number '1', '3', etc for all of issues 1610–1619. There were no supplements during this period so this function handles the 1610–1619 issues separately. The alpha character is always 'a' and is always separated from the digits and other alpha by a dot.