I think they will leave the blue canvas alone suspecting it to be a honey trap/ too easy. For that reason, when the mural is restored, I propose putting in for Greener, Safer, Closer, MmmBabyRightThere funding for 24 hour sniper presence on top of St John's's steeple. They can take down any taggers, as well as non-scooping dog owners and non-comedy tyro sex offenders. Half-serious suggestion - perspex or similar covers to 10 ft or so, that can be replaced reasonably cheaply in the event of repeat tagging.