There are already regulations forbidding the use of unapproved LED retrofits in housings designed for incandescent bulbs in most countries. The fact that your mechanic gets away with installing them, and you get away with driving your now-illegal car shows how well they are enforced.

Unless your car's design is particularly evil (a real possibility), changing a headlight bulb is usually easy to do yourself, and approved, incandescent headlight bulbs are easy to source most places.