9/10 on a new estate i'd say, i do council houses in kendal that size for £6, cumbria is hard to price though cos there is so many foreiners from down south who think our prices are cheap , where locals don't lol , ventwise spend as long as you need cleaning them until they are properly clean, it will save time & worry in the long run
dunno about else where but i dont find any difference in the time it takes to do a 1 month or a 2/3 month so i charge the same for all