quick easy way is when you turn your lights on if you have xenon discharge lights the beam on the floor will visably rise and level off.
The xenon discharge lights are a high voltage unit so its not a simple lamp change with halogen.
On a different note if the MOT test station picks up on the lamps having been uprated to LED its an automatic fail.
If you do go LED make sure you select a lamp that won't screw around with your canbus system and report a failed lamp.
Minefield - O yes!