Having to give them all again it's not only a major hassle, but it will require me plenty of time for preparation
Shouldn't do. The point of the exams is that you're supposed to know the stuff, not cram it for the exam and forget it the day after. In theory any one of us ought to be able to sit down with zero notice and pass any of our PPL exams
(He says, having let his IMC exam run out of time, so will have to do it again ... shall I do any revision, I wonder, or just assume that I learned it all properly the first time.)