everything in the article suggests they are looking to preserve this piece, not take it away from the city, I'm not sure where you believe your disagreement comes from, considering the inherently ambiguous definition of "ours". Thus far, the owner is out of pocket for security guards to protect the piece after someone vandalized it. In fact, most of Banksy's pieces have been vandalized, so sadly, it seems security is needed.

They were, confusingly, referring to 'No[v]. 17'. The prior sentence refers to a new day coming, which is 'No[v]. 18'. I have no idea why they didn't go with the accepted abbreviation of November as 'Nov'. They weren't referring to building number 17.

Just clarifying, not disagreeing with your statement :)