speaking as someone who works for an MOT centre and whos father in law is also a tester.
ANY headlight configuration will pass an MOT.... if the beam has a correct spread and cut off, is also alligned correctly and is no other colour than white or a number of variations (shades) i.e not blue, for example HIDS retrofitted to OEM H/L but with blue sidelights or blue angel eyes would fail, same setup with white sidelights or angel eyes would pass.
the common practice for the OEM H/L HID upgrade is to fit a shroud that redefines the beam pattern - however this is not always the case.
in summary, no matter what you do to the headlight aslong as there are no sharp edges, all the functions work (main, dip and sidelight) and the cut off and spread & allignment are correct it will pass. this however has NO reflection on the legal side. an MOT tester's sole role is to check the car is safe and is in accordance with VOSA's guidelines.
a good example being, i can pass a car that has 0.1m tread on the furthest part of the tread marker if there is sufficient tread on the rest of the tyre - the driver (with a fresh MOT) could be stopped just outside and recieve 3 points for an illegal tyre - just becasue it passed an MOT DOES NOT MAKE IT LEGAL.