Surely the more egregious ones (like effectively no dip) could be addressed at the roadside and the finer points tested at any MoT station if needed. About one in four drivers is taking the pee at the mo, with lights that are very high, wide or not even dipped, resulting in dazzle.
"Hello Sir. Show me your dipped headlights, then your high beam please?"
"No, I won't officer, because you're not a qualified vehicle examiner. You can check my tyres if you have a calibrated device and have have done the trainjng, you can measure my number plates if you have a calibrated (or new "in date" from an approved supplier) tape measure, if youre suitably trained you can measure my tints, if you saw me driving with a light out you can deal with that, but because you're not a vehicle examiner you don't have powers to ask me to operate any system on my vehicle and I commit no offence if I politely decline to comply."
"Ah, a smart arse. Did you know you had a tail light out? (SMASH!)"