[robbo333]

In future, get a few empty spray bottles from Wilko etc £1 each.
Tell them how fantastic de-ionised water is and how great it is for car windows. Each time you go back just fill up their bottles for free (as part of your service). They'll use it to clean their cars and think it's great. All of a sudden you've changed their perception of what you are doing. Works for me 

[Walter Mitty]

I lost one today as well due to not doing it the old fashioned way.
That hasn't happened in a very long time - at least if it has, they weren't up front about it.
It was a £20 house.
I will not compromise on this issue.
I'll go up on a flat roof if there's no other way - so long as it's safe - but I will no longer work off a ladder.
Apparently the person rated my well-being as less important than some cobwebs.  Personally I think that was an excuse but I'm not going to argue about it in case she changes her mind .

[Walter Mitty]

As far as Marc Stock (the OP) is concerned, maybe the best answer would be to get hold of an old piee of leather and give them a quick wipe .
"How old-fashioned would you like it sir?"

[capn sparkle]

As far as Marc Stock (the OP) is concerned, maybe the best answer would be to get hold of an old piee of leather and give them a quick wipe .
"How old-fashioned would you like it sir?"

Yeah mebbe turn up with 5ltrs of vinegar and some manky copies of the Daily Mail under your arm..... "Might wiff a bit to start with guvner - be fine in a couple of hours tho" .

Big smile.

Flounce towards their expensive looking offices.

Turn the whole place into a fecking chippie.

[Marc Stock]

Well it turned out that the issue was just one window. Right next to a tree. The polen from the tree would shed all over the window after the clean. So they put some translucent plastic on the inside of that window to reduce the effect. Apart from that they are happy with the cleaning so that turned out ok.

Sorry for late update work has been very busy.