You don’t have to talk to driving examiners!!
You will only have yourself to blame if you get carried away chatting, commit a driving error which turns out to be a failing point.
DVSA examiners try to get candidates to relax and will thus engage in a little bit of a friendly chat usually ‘breaking the ICE’ with the usual question ‘what would you normally be doing at this time of the day?’
At this point you can politely reply ‘sorry I don’t concentrate well on driving and talking’ and this will immediately let them know all you need are instructions.
As a driving instructor, I know from the many lessons they’ve had who my chatty learners are, and advise them accordingly to concentrate on driving and not being friendly with the examiner, as no matter how friendly they seem, you will still be failed if you commit a serious or dangerous fault.