Why does it take 85k to remove it from the wall? I'm pretty sure it doesn't cost that much. There is some ridiculous government inefficiency or embezzling happening or some kind of learned helplessness or malicious compliance. Just go, wash it off and done.
Rediculous government ineffiency is multiple redundancies. Just government. They could replace it with another commissioned Banksy for half of that.
This isn’t an American building where you buy a couple of two-by-fours and some plastic siding from Home Depot. It’s a historical building made out of stone.