I painted the downstairs loo a lovely shade of what I now believe to be hague blue (thanks mumsnet!) - the problem is that it is bog-standard ('scuse the pun) matt paint, not waterproof bathroom paint, and it leaves a mark every time someone splashes water on it after they've washed their hands...and it's really annoying me!
Is there some form of product you can buy to paint over a wall to waterproof it? I've had a bit of a google but nothing's really standing out as the right thing.