The green cloth helmet is a late G type, earlier G type were blue-grey. It did go inside Mk1A helmets but could also be worn on its own, usually in small aircraft such as the Chipmunk or very large aircraft such as transports and the V Bombers. The Mk1A should have been out of service by the mid sixties but I’ve seen one in use by a RAF Phantom driver. It was lighter and cooler than later helmets but offered less protection.

The mask is an A13 variant, designed and used in the US and later adopted by the RAF, in the fifties and possibly early sixties, for use mainly but not exclusively on US origin aircraft.