oh not sure about trying the nail varnish remover on the smeg fridge!
I have tried: furniture polish, wet wipes, washing up liquid, kitchen cleaner, and something must be working because it has significantly faded, and hopefully dh won't notice (phew!) DD1 is currently cleaning it with a cloth. Don't know if she was the culprit or her sister - but that sort of damage is done in a second, which is why I usually keep the biros locked away.
Thanks everyone!