HW,
Are you talking about PPL level? If so, I don't believe there is an interval you need to wait. Your FTO should be best placed to tell you, but I'm pretty sure you can sit a different paper almost immediately.
And you're right, I've still not worked out if the way the CAA word questions is deliberate, or because they can't phrase a question properly!
Good luck with the re-take.
DW.