It's a HSDR, made during the war from 1942-45, dark brown paint came into use in 1944. They also made them post war through the 40's into the 50's. Normally the liner is held in place by 4 rivets not screws.
The liner looks to be pop riveted in place.
Whatever its just an opinion.
It's been messed with. Are you thinking of buying this?
It looked like screws sorry, they should be domed rivets. The two at the front larger than the two at the rear. The Canadians I think had rivets like yours but you can see where the liner has been removed then put back in again. Just check around the rim of the helmet to see if there is a date/maker name.
The first picture is Canadian, the other 3 British HSDR.