Gave it a wipe when it happened and thought that was it... but it wasn't.
It was saag aloo and has left a greenish mark on a black sparkly cheapo worktop. I've tried Method and Humblestuff on it because that's what we have in.
We have some lemon juice, and bicarb, and some of that black mould removing Cillit Bang. Would any of those be any good? I have no idea what I'm doing.