I would personally be very wary of pricing up a job like this without being able to actually see the building in its completed state.
There are so many variables that might bite you in the arse when you come to do the job.
I would never give an hourly rate, but a buildinf 170m long is huge!!
Daivid said put in a silly price of £800............I don't think that sounds silly at all
You could perhaps say that a charge of £400 per night would apply, for this type of work, and with 2 people I would expect to earn this much in four hours, particularly such unsocial hours.
If the building is one of those with almost all glass that is a huge amount of glass, 170m by 7m is a lot of glass, then there are the 2 sides and the rear of the building too.
I wouldn't fancy the initial clean if I had to knife off loads of silicon though
Cherry picker time
I've never done anything remotely approaching that size though, I have a job even visualizing a building 170m long covered in plate glass
No way would I feel confident enough to price it by looking at the plans only.
Best of luck though.
Thinking further I reckon £800 would be pretty cheap.
How many panes of glass in the building, and what size are the individual panes?
Ian