Gas Locker Hinges

Hi, can anyone offer some guidance ...

I'm new to caravanning, and have a 1983 Castleton Roberta which I got from some friends (they owned it from 1987), and is in really good condition apart from a broken Gas Locker Hinge.  I tried previously looking for the part but failed and so tried making a replacement in acrylic, but that sheared away after a couple of uses of the locker (as I was afraid it might!).  I would like to keep the gas locker as unmodified as possible (I don't really want to start drilling holes in it as it is shaped around the hinge area) so am try to find a replacement, or something that I can modify to be so!.

I have posted a few pictures of the hinge/hinge parts here ... ( http://dl.dropbox.com/u/23210539/Caravan/hinge-2.jpg ,  http://dl.dropbox.com/u/23210539/Caravan/hinge-5.jpg , http://dl.dropbox.com/u/23210539/Caravan/hinge-8.jpg ) 

If anyone can offer advice as to where I might be able to find (similar) part, I would be very grateful.

Ta.

SteveTR