i found some in the end 100 for about £10. but i have just found out the job in on a wall, not facsia.
Its marker pen on a white wall saying "what a lovely clean wall"! hmmm :

....anyway, im going to try these wipes, failing that jet wash it, failing that i have to paint it.
Does anyone use anything to stop the pen from seeping back to the surface after ive painted it?