£30 x 6 actual working hours= £180
£180 x 5 days = £900
£900 - Van, fuel, some advertising, system, filters, poles, accountant, stationary, etc etc.....
= Not really that much in comparison with any other job!
Im sure there are plenty of window cleaners out there on much more than £30 per hour. They just don't come on here telling everyone about it.