Just looked on here and seen a round worth £300 monthly + £80 6 weekly, asking price, a snip at £5700. A lot on this site seem to be priced similarly. Has anyone on here managed to sell at over 15 the monthly value? Or dare I ask has anyone bought? 
Its a simple case of supply and demand. Jobs are in demand, businesses are struggling people dont have work. Window cleaning is a relatively recession proof business, especially if you have alot of wealthy customers, or long standing clients.
Some after 10 years of service are being made redundant or being made to take volentary redunancy. The lump sum can be quite a lot and to buy a window cleaning business can give some security. Its in demand, a chap i knew was selling only 25k worth of work, he got offered 8 times his asking price due to the ammount of people looking to expand, or get into the trade.