What mark you give? Unless it's coursework for an external exam it doesn't really matter that much. Do you have to give a mark? Can't you just leave a brief comment? Just give 'em a mark. If they moan at you (and only if it comes from them) then you say one of the following: 1 You're quite right. I think I under-marked you. Have an A+. 2 It was a thin line between A and A- and I think I got it right. Byee. If they don't contest it? There's no problem.