Nope, not something new. Was there when I passed my test in the '80s.
You MUST NOT
use any lights in a way which would dazzle or cause discomfort to other road users, including pedestrians, cyclists and horse riders
use front or rear fog lights unless visibility is seriously reduced. You MUST switch them off when visibility improves to avoid dazzling other road users (see Rule 226).
In stationary queues of traffic, drivers should apply the parking brake and, once the following traffic has stopped, take their foot off the footbrake to deactivate the vehicle brake lights. This will minimise glare to road users behind until the traffic moves again.
Law RVLR reg 27
And it refers to Rule 226 which is:
You MUST use headlights when visibility is seriously reduced, generally when you cannot see for more than 100 metres (328 feet). You may also use front or rear fog lights but you MUST switch them off when visibility improves (see Rule 236). Law RVLR regs 25 & 27
(taken from the Highway code)
The highway code uses 'Should not' and 'must not' and they are distinct, should not is guidance, must not is absolute. And it is in capitals. I think they mean it!
I am not sure about use in connection with a medical condition but I don't think you can use it as a defence in this country and the law might state that if you cannot drive at night in accordance with the highway code then you should not drive however I am not a lawyer.