Martin, looks like you also read carpet cleaning instead of office cleaning - and this is the 'General Cleaning' section of the forum.
Mark's looking at the work that involves emptying bins, vacuuming carpets, dusting/polishing, toilet cleaning etc.
I've also tried to find Mark's comments about an initial/deep clean - but I'm damned if I can find it.
Our Mr Betts is clearly a very experienced carpet cleaner - I don't think he needs help on quoting carpet cleaning, but office cleaning is something he is looking to diversify into - hence his request for advice.