Women's WW1 UK Military Records Index on Ancestry

Ancestry has added indexes to two data-sets from The (UK) National Archives

Web: UK, Women's Royal Naval Service Index, 1917-1919 with 7,444 records
Web: UK, Women's Army Auxiliary Corps Index, 1917-1920 with 7,010 records

The naval index search provides name, enrollment date, service number and rank/rating (occupation).
The army index gives name, birth date and birth place.

Both provide a link to the complete record, with images, at TNA's Discovery website at a cost of £3.30.