A little apprehensive to tell you what I would charge because of the potential fall out,

It does depend really on the area, does furniture have to be moved? if not and you cleaning around desks, computers etc how far apart are they ? " cluttered working areas always a premium price in my eyes". what method will you be using ? and numerous other factors.
my price , for a large area , open space as little as £1.00 per sq yd using encap , now you will have to adjust accordingly . What systems have you at your disposal/
geoff