Hi
It's very difficult to price generally but a typical wage to charge ratio for a contract like this would be between 65-75%. On top of your wages you have to add management time, materials and equipment, training costs, workwear and profit. If the cost of wages was £10,000 (have you included NI costs, holiday pay, etc?) then I would expect the contract value to be in the region of £16 - 17,000 per annum. If it's 3000 square feet then that would equate to £5.50 per square foot or £49.50 per square metre but that seems very high to me and I suspect there's something not quite right.
How did you come up with 4 cleaners? Are they each working 1 1/2 hours a day?
Regards
Mike