The reason why you as an academic scholar should not go into the dsa practical car test with the belief that you will pass first time because you haven't failed an exam or test before is because the UK driving test is not an academic examination, and thus you have no previous experience of this type of test before now. You will be using psychomotor skills, and unless you are lucky enough to have things like flying lessons, ride a motor-bike are in new teritory and need to make sure you get enough practice before booking a driving test.
One of the special skills that is being tested on the dsa car test, is the ability to think on the move, you need to make decisions pretty fast while on the move, this is different from your master's degree exams where you can skip a question, take time to consider the options available or brood over the essay that you are about to write.
On a test manuever, you have limited time to carry out proper observations while the car is moving towards a pedestrian walking on the road, you need to act quickly on approach to a roundabout, deciding when to brake, what gear you are going to use, consider if you need to stop, slow down and give way, etc. It is a whole different game ball, so academics does not come into it at all, so being an A1 oxford graduate doesn't mean you will ace your driving test.
Talk to your instructor, and make sure that you don't under-estimate what is required by the DSA examiner, and only then can you be sure you are adequately prepared and have the best chances of passing with flying colors, achieving the goal of a full british pink driving licence. Remember the theory test is just another academic examination, and therefore no indication of how your psycomotor skills will perform during the 40 minutes test with the dsa examiner.
Important! If you are not learning to drive with an instructor, it is important that BOTH you and the person teaching you to drive read The DSA official test guide, this book will greatly increase your chance of passing the driving test without spending too much money on lessons.
More Driving Test Advice
Top 10 reasons for failing the car driving test
Reversing Manouvers Advice.