11.—(1) When appropriate, having regard to the risks to the health and safety of end-users presented by a lift, the installer must investigate complaints that lifts installed by it are not in conformity with Part 2.
(2) An installer must keep a register and promptly make entries in that register of any—
(i)complaints; and
(ii)lifts that are not in conformity with Part 2.
(3) An installer must keep an entry made in the register for a period of at least 10 years beginning on the day on which the obligation to make the entry arose.