This may be a European law, that's necessary because people with UK licences may use them in Europe and vice versa.
The committee that advised the EU on this included people from several different countries including the UK. The outside consultant on hypoglycaemia was in fact British but if you read the report it seems the question on nocturnal severe hypoglycaemia wasn't specifically addressed as a separate issue.
There was a petition about this a year or so ago. I mentioned to the complier of that petition that if he wanted to get authorities evidence he should perhaps contact the external advisor. (he might of course not agree)
The advisor was Professor Prof Brian Frier. He has written many articles and the standard text on hypoglycaemia. Perhaps you should contact him for his views . Until 2012 he was the chair of the DVLA diabetes medical panel.
http://www.cvs.ed.ac.uk/users/brian-frier
(though, maybe, I should be complaining that because of the high British influence people on the committee which means T1s in France now have to go before a medical tribunal to review their licences! (personal doctors are not allowed to reveal confidential info so a state employed doctor is used)