they seem to basically hose the windows down with a garden hose, fed from a backpack of what I can only assume is purified water. It wouldn't sell to me, but from there list of areas they seem to do ok. I have seen there website before though, there was posts a while ago about there satellite quoting.
They come across a bit naive if they think the can quote jobs using google earth, and come out and literately hose down the windows for the customer.
whooo weee
I bet they get a few cracking comments from customers, "honey that's the gardeners at the window!"