Old, 1950/60? "electrolux 23" caravan fridge?

Does anyone have any info on this model re starting it up and/or trouble shooting & repairs? (I am only guessing it's age). It is gas/electric. It has not been used for a couple of years and is now not working. It has a push/pull lever thing below the door and a plastic rod inside Left along to the bottom left corner. The rod is not labelled and has a counter-clockwise arrow on its knob. It will turn ad-nauseum so I don't know if its broken or what it's meant to do. There is also an Electric dial and a Gas dial. The only way to get at the rear (to investigate) is to remove it, but it has somehow been plumbed in to the gas with copper pipe. They say what goes up must come down, so i think the next step is to get a torch and a mirror to see how. Any info is welcome.