Perhaps if the affected stone needs to be replaced (As suggested on Radio 4 this evening) the whole memorial should be moved to Air Cmd.
I wondered that myself at the time as Sandstone being porus the paint will soak into the stone and be nigh on impossible to remove...
Look at that other historical sandstone building vandalised, that had to be painted white after the Brits of old passed by and torched the place, the soot and smoke had soaked into the stone around the windows and doors which was impossible for them to remove....
Ohh and the place the British vandalised way back in August 1814
Here endeth the history lesson
