Enough to put me off wfp that is!
I'd have done at least 3 or 4 in that time.
I'm with Squeaks on this one!
That clip was overkill in a big way, if I took that long, even on a first clean I'd jack it in!
A single pane of that size on a first clean should be done in no more than 20 seconds....which is slower than it would be done trad admitedly, but first time cleans with WFP are usually slower than trad anyway.
But as for Gary's problems....
It may well be the frames that are causing the problem as Vince says, but it wouldn't necessarily have to be powder coated frames for that to happen.
if they are oxidising you may get problems. period.
Try them again, make sure your brush is very clean, the vikan broshes are flocked bristles, many use them without a problem, but they are also the brushes most likely to keep hold of contaminants.
Wash just the glass, don't go overboard (as in that video clip) if the frames are the problem, excessive washing will only draw more muck off them.
Just do the glass, finishing with downward strokes and then carefully rinse off the glass, directing the jets accurately so you are not flooding up into any gaps that may be between frame and glass.
Before you unleashed yourself on your customers you should really have practised on some family and friends houses first.
If nothing else you would have gained a little experience on different types of windows, and also as you would be doing them for free and they are people you know, there would be no pressure on you, you could take your time, check your results, go back over bits and so on.
But on your own windows they may simply be ones that will never come right with WFP, it happens, you just have to accept the fact that sometimes WFP just isn't suitable...
So therefore when you get accounts that are like this, you either do them trad or do the upstairs WFP and downstairs Trad and tell the customer that is the way it has to be from now on.
Ian