I bought a Volkswagen Polo 2006 (06) 1.2s in April 2012 from a main dealer.

The car is under a years warranty and since purchase I have had to have both window regulator replaced on the front windows.

Recently I have noticed a fault with the handbrake warning light, when the ignition is turned it lights up when the bulbs 'test' and then goes out - but when the car is started it doesn't come back on, which it should.

Sometimes it will come on when I apply the handbrake and sometimes it doesn't come on at all.

4 Questions:

1) Would this count for an MOT failure if the handbrake warning light isn't active?
2) Would this be covered under my cars warranty?
3) If I decide to have it investigated what cost would I have to pay for the main dealer to diagnose the fault & fix?
4) Is this a common fault on VW's (Polo)?