Hi Seamus, the question about operator productivity is a tough question to answer, given the environment you are cleaning has so many variables, including amount of spoilage, shelves, floor type, access ect.
I can say that in a normal office cleaning environment a well trained cleaning operative can usually clean circa 2,000 to 3,000 sq foot per working hour, on a normal cleaning schedule and dependent upon density, occupation and floor type. Also a typical scrubber dryer will clean 2,200 sq ft per hour. (excluding set up and preparation time)
Now here comes the hard part, how many cleans will it take to get the area to the right standards, some site managers instruct tradesmen to clear up after themselves so their work can be validated, some site agents leave it all to the cleaners to do, clearing waste, refuse and sometimes rubble from a site before the cleaning starts can be a time and cost consuming effort.
And then you have the repeat cleans, snagging and interruptions, my advice would be to charge a daily rate per person per day, if you get buggered about and are waiting for areas to become free it's at the clients cost not yours, if you have to provide a productivity cost and price off plans I would assume a really low productivity rate in the region of 500 sq ft per person per hour, assuming that bugger about factor will kick in.
Good Luck and best wishes Seamus
Cheers
GeoffDerby