short days DONT cost you time if you finish about 4 pm all year round!if you work in most wet weather as well then you wont lose too many days.lack of motivation?whats that?i very rarely lack motivation!hangovers?I DONT DRINK!
£10,000 on expenses?more like £5,000 for me!
as for £10 for a 3 bed semi.i charge between £7 and £12 on very compact estate work making £150-£180 per 6 HOUR working day.i have 8 days of very compact estate work.of course i have lots of other high end accounts and some nice commercial jobs(mainly mid size offices,childrens homes and nurseries).
plus all the add on jobs conny roofs,fascias,soffits and now solar panel cleaning.
fuel costs per week average at £15 in diesel.
collecting averages about an hour a week as more and more customers pay online,SAE or are in and pay me on the day.some weeks i dont collect at all.
i can complete most of my work working 6 hours a day 5 days a week over the course of 3 to 3 and a half weeks.some of them days are only 3 or 4 hours!quite often i get 3 OR 4 DAYS OFF or sometimes a week off MOST MONTHS!!
being organised and using extreme poles and a high flow with aqua-daptor i burn through work so fast at times.
ive still got plenty of time for going the gym/swimming and helping my missus in her shop and holidays and i hit the higher end of your figures you ve quoted ian! 
oh.....and.....login in on ere!!!

Nice response Daz but if you do all that you - I'm not doubting you by the way - say you do, then you represent...let's say the 'potential' for what can be achieved.
Very few of us will work in all extremes of weather, most will most certainly be affected in the depths of winter by short hours.
One thing I will disagree with you on though is business costs, your work vehicle alone - regardless of whether it is your only vehicle - is 5k worth of overhead alone, vehicles don't last forever, plus you have to spend money on equipment, pumps, batteries, poles - and the good poles are expensive poles! - brushes, resin, all trad gear too of course plus pressure washers and assorted gear that goes with them if you use them, then there is workwear,cold weather gear, waterproof boots & gloves for the winter and so on.
Much of course is 'possible' in fact, if I only had what it takes I'm sure I could emulate Richard Branson, have my own chain of shops, trains and mega empire...all is possible.
It isn't of course, just as most window cleaners will be darned lucky if they even turn over 25k let alone have an income of that size that they will be taxed on....
Want an honest answer for income? Look at the income you are actually taxed on.
Not sure what the tax man states as the average turnover is for window cleaners now but about 3 years ago (roughly) it was below 17k and out of that has to be taken all business and running costs.
I do know of a couple of window cleaners that have some amazingly high turnovers and the prices they charge match their turnovers too and one is on this forum too!
I wish to hell that I could charge what he charges but the best I can do is stand back and shake my head in envious admiration...