Dexter,
I think you've done very well in a short space of time. Before you canvass anymore, get window cleaning so that you can experience what you've quoted for. You'll start to find out all the 'little funnies' that can make a job awkward and why you may want to quote more for them.
As for the Working Man's Club, £50 sounds good to me.
I base my price on number of windows, access issues, and frequency of clean. I try to quote around £1 per window (big or small; it tends to even itself out), more for big bay windows (I may as well), leaded and georgian; oh and I'll charge £2 a window for 2nd story stuff; and then I'll add more for any access issues (which includes travel if it's a bit of a drive and I haven't got many around there); and frequency. If the customer wants a longer frequency, they're worth less to me, so I'll charge a little bit more.
The guys here may charge differently, but that's the way I tend to do it - but I'm pretty loose with that I suppose. And when faced with a property, I've no doubt got something like it on my books and I can compare it with what I charge already.
Anyway, you seem to be doing great.