Many pupils are initially alarmed when I explain that 10 minutes of the driving test is set aside for 'independent driving'. Most immediatley feel like this because they wrongly believe this to be a test of navigation, whereas what it really is designed to do is to test the candidate's ability to drive in a more 'real life' environment. So anyone worried about going the wrong way during the independent drive can be reassured that it wouldn't result in a fail. If you check the correct mirrors, signal at the correct time, and then carry out the manoeuvre suitably then it doesn't matter too much if you miss a road sign. Should this happen, the examiner will step in and guide you back onto the correct route where you would continue with the independent drive. If you're following diagrams instead of road signs, simply ask the examiner to repeat the instructions if you're having a problem remembering them.
The thing that tends to suffer most when first attempting independent driving is the MSM routine. Learners are often so intent on looking for road signs that they can forget correct mirror checks and sometimes even a signal before carry out the manoeuvre. This, in my humble opinion, is what you as a learner should be concentrating on, rather than worrying if you've gone the wrong way!!