While at the markets today I ran into a bloke. who has a 20 inch Metters lid. Hes keen to do a swap for anything collectable....the bloke in question is a keen collector of old bottles, tools and kitchenalia, he wheels and deals in alsorts of stuff so is possibly open to a wide variety of collectables as a swap. I had a good look at the lid and its well marked " Metter 20 inch".....some surface rust but not pitted........overall Id rate it very good condition and I think it would clean up really well.
If anyones interested let me know and I can put you in contact with him
Rory