I don't know if it's a fact Shaun, but you might be able to pass it off as a statistic. Anyone who feels my maths, numbers, or logic is flawed please come in.
1st From canvassing I would say that 95% of people have or want a window cleaner. 5% do their own. I have never met anybody who admitts to not cleaning them.
2nd If we define a Round as the number that can be comfortably done by one man in one month and agree that this number is 400 customers.
3rd Therefore a window cleaner should live in 1/400 of the available Uk housing to meet this demand. This is a very large number, something like 250,000.
4th what was the question again Shaun?