Every light aircraft has a MEL. The SEP FAA MMEL which is a devil to find on the net and keeps moving. The UK just references that one.
Now hold on a sec, just out of curiosity, do you have a source to such a regulation? Just because there is a MMEL does not mean you can operate with that as your MEL. Are you talking about commercial or non-commercial aviation?
I have not been able to find anything conclusive regarding what does or does not have to work during flight, except vague statements that anything that is not required for the flight can be broken (e.g. landing lights during daytime).
Edited to add: BTW, according to that MMEL, the landing light is Category C, i.e., only 10 days deferable...