Having xenons retro fitted is fine and not having washers nor levellers is NOT an Mot failure.
What I would recommend is to change your halogen lamp adjustment switch on the dash for a xenon type switch, as the switch could be seen as inoperative and deemed faulty, as the roller on it doesn't do anything once you change to xenons.
From what I've read, you only need to be concerned if you've fitted hid bulbs in Halogen housings as the beam from them isn't the correct beam that was designed with these lenses ,and this could blind oncoming traffic..!!
Hth