Masonary painting

I guess the fungicide would be a clear liquid so may not leave signs when dry, but one imagines they would have have applied it over the whole building before starting the painting. If the edges are dirty, it rather sounds like that hasn't been done. Masonry paint is well able to bind up reasonable amounts of dirt and grime, and almost certainly contains its own fungicide. I doubt the pre-treatment would make much difference but obviously you shouldn't be paying for it. I might ask them to show me the empty fungicide containers....

Tell them to go to Hell.

Did they start that day? I'm assuming that this is a reasonable sized building. If so they really haven't had the time to clean down (wet?, let that dry) apply the fungcide and presumably let that dry as well and paint

They don't appear to be fullfilling the terms of the contract (under English Law a verbal statement and agreement forms a contract, though can be impossible to prove one way or the other).

If that piant doesn't contain a suitable fungicide get them to remove it all, properly clean down, apply fungicide and/or fungicidal paint all *at their expense*.

I have written them a letter asking them to confirm in writing that they are complying with the specification (which they included in their quote) also stating why I am doubting that they are compliant.