Hi Gofish, just saw the piccies, big(ish) job there. What Dave says makes a bit of sense (about the state of the frames) if possible try and get a pre clean(that is get them to let you do a couple of practice windows to see how they come up with the WFP and the technique you use.
This way you could save a lot of hard work trying to fetch them up clean enough so you can get paid.
Viz; had a job once, quick look round, priced up, accepted, did the job but it did not come up clean using normal technique due to bad frames, old residue leaching out from cracked putty/paint lifting and breaking off in little pieces, what a nightmare.
So advice is, try a couple of test windows before hand, especially if they have not been WFP before, and check these from inside as once started, must be finished reasonably clean before payment is made.
Sorry about the longhand way of saying it.
And please could I have a look at your letter. (Lancs area)
rdwc@hotmail.co.ukThanks in advance and good luck.
Steve