oven door closer needs modifying?

A very old Regethermic regeneration oven - has this old door closer which is useless, it keeps getting jammed, no parts available etc etc.

So I'm looking to get around it. It's a side-opening door. Am thinking magnets (not sure how that would cope with the heat), or a swing-arm latch across the door. Basically any reasonably simple solution that will do the job for a couple of years. Any suggestions would be great.