According to my calculations that is only 463m2, at £2.59/m2 with your discount.
Without seeing the job I would expect two people should comfortably knock that off in one day without any problem.
I would have gone in at £1.10/m2, around £510+vat for the whole job, and I expect there are others who would price similarly.
If you get it well done. if you don't. don't be surprised.