i'd get a metal one ... they last longer.....
sorry about that ... couldn't resist !!! I have no idea though , but if you can't find anywhere that sells them , then any good blacksmith should be able to make you one up . When I say blacksmith , I mean blacksmith as used to be , not the modern sheet fabrication welder type of blacksmith . I have asked some of them to make something and they just looked at me like I had two heads !!! So I learnt myself . Sorry can't help anymore than that ...
cheers
Russ