If you go onto Council websites and search census then you should come up with how many houses are in the council area.
Yes window cleaners in licensed areas need to be licensed , the problem is only around 35% are licensed which leaves us at a disadvantage. We should all be at the same level, insured and licensed. Then the £2.50 pundits will stop, this is our living wheras others use window cleaning as pocket money but do not have the costs we inccur.
Any other trade would be up in arms, so hence the SLWCN was formed to highlight these problems to the councils. So far we have had success with one council who will publicise all licensed window cleaners on their website, hopefully more will follow.
Your figures are near enough to what we will use, we estimated 551 window cleaners and only 193 licensed.