M&s is a classic case they have a twice weekly, fortnightly, 2 monthly and a 4 monthly spec, with cafe windows and what's classed as above head height being on the 2 monthly spec. A local window cleaner inspected the store and pointed out everything that was dirty about the store to the store manager without even knowing what the spec was, he was hoping to get the job, direct from the store manager, And get me in trouble, which would never happen in a month of Sundays.
Some of these stores are massive, and only selected windows are cleaned on each visit, they never have all windows cleaned at once apart from the 6 month & 12 monthly spec .