Hi Pughy - a few ideas -
Have you got her husband's death certificate - was she the informant (ie would indicate she was alive in 1926)?
Have you looked for a second marriage - I realise she would be over 70..?
Have you tried "soundex" searches for spelling variations?
Was she legally something other than Annie, eg perhaps Ann was her first or even middle name, or Hannah/Susanna etc?
Sorry - no answers just suggestions for more searches