Hi jo this may well be a 6 floor job its big there is a lift but all water only on ground a bummer!I will take another body or 2 if I get the whole job
on each floor,there is 300ft to the left and 300ft to the right :
so I am finkin that money for the aggro 
Am I reading this right
6 floors
each floor 2 x 300ftx4ft or 2 x 100x1.3 yds = 2 x 133 sq yd per floor = 266 sq yd per floor
= 6 x 266 = total 1596 sq yd
If that is correct and you go at £1.50 sq yd then that is about £2400
You may want to consider low moisture cleaning as in rotary.
Get a machine of ebay - £200
a load of pads say 20 at £15 each = £300
some fluid, bits and bobs say £40
£540 and you got the right gear for the net commercial job.
but you may have to go in as low as £1 sq yd to get the job if your competing. Thats still £1596, less the £540 for rotary etc = £1000 profit (less wages of your bucket boys) and you still got the gear for next job.