The handguard ring comes right off of this one. It expands once you take the screw out. Maybe because it's too thin? It was a tight fit but it did come off.

It is definately a No 5 MK 1 ROF (F) rifle. I cleaned the metal off and can read that clearly now. I still can't make out the date but appears to be 2-46 as 2-43 would make no sense for this rifle. I may try a pencil rubbing but something tells me that isn't going to work.