Thanks for replys so far.
As this is a regular window clean customer that ive had for years, I dont need to quote it, just go ahead and clean then send the bill in
I reckon it will take about 4/5 hours.
It doesnt look dirty in the pictures, but it is quite bad when your close up.
My plan is to fill tank with tap water, then just pump straight out bypassing the DI.
Nice little earner when I eventually get round to doing it.