WOW thank you guys, things make sense now. This oven is also exactly 20 yrs old.
Initially it was missing the internal fittings, the rack to hold this particular plate too. I managed to get a similar scrapped oven that had the rack and a plate covering the burner. Initial use of the oven without it resulted in an exploded hardglass bowl :-(
I got it all to work now, disassembled and cleaned the unit and it is in as new condition again! (Picture doesnt show the rack yet).
