Lucy, you are quite correct: the Marriage Act says
Notice of intended Marriage. In every case of intended Marriage, it will be requisite that one of the persons intending Marriage give notice, under his or her hand (in the form specified in Schedule A. annexed to the Act), to the Registrar of the district in which one of the persons shall have dwelt for not less than three days; and if they dwell in different districts, notice must be given to the Registrar of each district. The notice must state the age, name, and surname, calling or profession, condition, (whether bachelor or widower, spinster or widow), and dwelling-place of each of the persons: — also, the time that each of them has dwelt in the district, and the Church, Building, or Place in which the Marriage is intended to be solemnized.
..... that being said, errors..... answers to the question 'how long have you lived here?'...... could well have been interpreted by the people themselves in different ways. I'll be cautious with the ITM but its really useful for firming up ages where the marriage reg only says 'full age'... and if there was a relative to give an underage person away. thanks a lot for your post which has given me the correct answer!
cheers,
Louise