Haha Neil, I just got a call with the square meterage and address of the property, looked on google street view and priced it from there, I even priced it about £30 more as it was abit out my way (travel time etc). Initially he wanted just the front doing but when I got there to do the job he asked abut the back, I just said just an extra £40 while I'm already here, only took about 30mins, he never wanted me to resand it mate.
David, I run an interpump 2030 but only have 2 x 03 nozzles in the surface cleaner so doing around 20lpm, also I get a few extra bar out by tweaking the unloader (which I thought was a bit naughty at first) but the engine can more than cope with the extra pressure, even though the pump is only a 200 bar pump it still copes well with it, ive been running this setup for around 18 months now with out problem. I just came to the conclusion that the larger pumps are built like tanks (everything is oversized and built for the job) and are design to cope with a bit extra pressure.
As stated I also put it down to the mosmatic playing a bit part in it, whirlaways are better on flags as you can walk quicker with no ringing... mosmatics seem to leave more rings on flags but they are superb on mossy block paving, the pictures speak for themselves