I'm a professional window cleaner, and I can tell you that in my opinion £2,000 for the building you just described sounds about right.
A good window cleaner will use a pole system (usually reach & wash) on this type of building. If they are using ladders be sure to check the building owners H&S policy, as there may well be special mention of work at height.
In any case you should obtain a risk assessment from your window cleaner. (This may cause them to whinge, but you absolutely must have it)
Something else worth noting :- I regard subcontracted window cleaning work as pretty low. Most commercial window cleaners hate that type of work, they prefer to deal directly with the building owner themselves rather than through a general cleaning contractor. This can often lead to poor standards of work (especially if NOT using reach & wash) which you must be careful to control.
Having said that, some window cleaners love it so you might be lucky.
Another point from experience: I have quoted for window cleaning at commercial premises where the window cleaning is tied in with the general cleaning contract. The building owner was not happy with the window cleaner so asked us to quote, which we did. Our quote was substantially higher than they were paying their cleaning contractor.
The reason was that the cleaning contractor did not itemise "window cleaning" correctly on their invoice, making it appear very cheap. (Less than £1 an hour) They did this so that the building owner wouldnt be able to find a cheaper window cleaner and would have to continue to go through them.
But this backfired, because they then lost the whole contract because of the rubbish window cleaners (who kept damaging cars).
Had they just put the real price on, they would have kept the cleaning contract, and the building owner would have dealt with window cleaning seperately. (they probably didnt make much on the window cleaning anyway)
So my advice to you is itemise it correctly, dont try to pretend its cheaper than it is just so it appears that you are giving the customer a good deal. Lots of companies do that and it drives me round the bend!
Is this a common practice in your experience Fox?
Better still, tell the building owner that they will save money by dealing with the window cleaning themselves, they'll thank you for that and it will save you a load of bother. And if they arent up to standard you wont get the blame.
There's no shame in not having "in house" window cleaners, many large cleaning contractors sub out windows.
-Philip