sometimes the £1 rule does not exist with me, ... i have to look at a job and price it by the hour, otherwise i would have to charge over the top rates, as sometimes there are too many windows, even on an average semi..... to price by the window... and i would not get any of the jobs i quote, in these cases.
if i think a normal semi might take me ten minutes, and the next one has a couple of extra windows, or an awkward one, i just add a quid or two on.