do a search mate, its been covered so many times. LOADS of people pass, a few dont. At your own risk kinda jobbie as 'technicaly' the leon lacks several features required to make them absolutely 'legal'
 
My car passed its last MOT with them on. The only reason I can think of why they wouldn't pass an MOT is because the alignment might be out. The MOT doesn't cover testing for things like auto-levelling and washing so you can't fail on it.
 
Mine passed with them on (8k HIDs) but was advised quietly by the tester that the alignment and beam pattern wasn't ideal (possibly due to my fitting rather than the bulbs) so I've gone back to standard bulbs ... your mileage may vary and depends possibly on the relationship you have with the garage doing the testing :)
 
Mine passed with them on (8k HIDs) but was advised quietly by the tester that the alignment and beam pattern wasn't ideal (possibly due to my fitting rather than the bulbs) so I've gone back to standard bulbs ... your mileage may vary and depends possibly on the relationship you have with the garage doing the testing :)

the standard leon lights dont have a very clean 'cut off' more a fade. So if you fit hids then some may decide that the light pattern is not acceptable.
Projector headlights have a cleaner cut off and so are more suited to hids.
 
I have 6K HID
Went through the MOT last week with no issues with the lights
Exhasut mounts were antother issue but i won't go into that