Help, just noticed our newly painted office has had a minor leak from above leaving brown water tracks down the walls. Any good products out there to clean them off, or is it a paint over job?

If its an emulsion then you'll have to re-do...you cant get the stains out. As you lift the stain you will lift the colour of the paint with it so you will end up with a slightly less brown stain and a slightly less colourful wall.