I would think a Europe or Middle East modification.
The liner originally could be WWII manufactured, but post war modified.
The big suspension A washers and Studs are the signs.
Or, simply the whole thing is a copy of the WWII liner.
What's the maker of the liner? (There should be one or two stamped inner top of the lid)
NIKRSM imo Taka is correct it is of European design and I am under the opinion it is an early French liner for the M-51 they are very similar in construction to the American M-1 .
I am by know means an expert on these and this is just my two cents worth but I do notice some striking similarities to the helmet liners posted in this thread the enlarged suspension system,washers and studs.
French OTAN M51 Helmet
Always on the look out for WW II Canadian Helmets and Cam nets to add to my collection.
Found a Canadian Mk II Medics Helmet and yes I know they are about as rare as hens teeth !!!!!