Looks looks a nice condition Mk2No.1 for use on the home front, with the remains of a Mk1 anti-gas curtain.
Or a posh carrying harness, but most are made of canvas.
These your comments would be consistent with the information of the person who gave it to me.
According to him this helmet is a private purchase of an Officer; this would justify a carrying harness, or a rim protector, made with better materials and even the particular coloration.
Always sorry for my bad English!