The new DSA Show Me Tell Me questions take effect today the 1st of July 2008.
Your driving instructor should have made you aware of these questions, and you can now be expected to answer some more basic car maintenance questions about the head restraint, fog lights, ABS system, etc.
If you have been preparing for the driving test without an instructor, you should check the driving article referenced above for full details of the changes to the show and tell questions that the DSA introduced this july.
Note: You can't fail the driving test presently if you fail to correctly answer these show and tell me questions, you will only get one driving error, leaving you with 14 more for the practical part of the driving test.
New Driving Test Changes for October 2010.
Theory Test 2009, case study questions.