have a medium sized crack on front sidelight - wondering if anyone can advise me about what glue to use ( the mechanic said this was ok - cyanoacrylate based glue like Loctite or something

but is this the best way ?

apparently you dip a needle into the loctite and push the glue into the crack and it bonds and seals it in 10 minutes or so, then use very fine grit sandpaper to remove excess

Not sure that will pass an MOT, as I thought light lenses must be intact as not to impact refraction. 2015 Range Rover Autobiography 4.4 SDV8

I just spoke to my MOT man after work, and he is OK with the lens being repaired, the material is just Polycarbonate, and the cursory look at the headlights and sidelights during the MOT is nothing more than to see if the lens is clear ( not all fogged up or crazed all over etc ) , the more crucial part is all the lights/lamps work

The idea is to repair the lens so that you cannot even see if it has been repaired or not - and that would make it extremely difficult for any MOT tester to spot any repairs in the first place !