20.—(1) Works or activities forming any part of the authorised development must not take place on Sundays or public holidays or other than between 0800 and 1800 hours on weekdays or other than between 0800 and 1300 hours on Saturdays, unless otherwise approved by the relevant planning authority.
(2) Nothing in paragraph (1) precludes a start-up period from 0700 to 0800 hours and a shut-down period from 1800 to 1900 hours on weekdays, excluding public holidays. During the start-up period and the shut-down period, no activity must take place on the site that is audible at the site boundary.
(3) Exceptionally, short-term works outside the normal permitted hours and days may be agreed with the relevant planning authority or permitted under section 61 (prior consent for work on construction sites) of the Control of Pollution Act 1974(1) and the conditions attached to any consent must be complied with.