Replace obsolete electric fan oven thermostat Stoves DF550SI

[Dce]

I have a faulty obsolete (20yr old) oven thermostat incorporating a separate oven fan/light switch tab. Can't find a 'universal' replacement. If I fit a standard 2 tab thermostat, and connect the fan and light, they will switch on and off with the element which is not ideal.

I have a Stoves single oven cooker DF550 SI with a 46thc502/G5 thermostat which controls well (if 40C higher relative to the oven thermometer). However after an overnight cool-down, the oven element switches on when the mains is turned back on, even though the oven control is off. I just twiddle the oven thermostat control slightly and all is well. Or I can leave it and it goes off by itself eventually.

I can't find a 250C, 1m capillary phial, 24mmx6mm spindle thermostat with a separate connection tab for the fan/light anywhere.
Otherwise the oven works and looks like new (nearly). I was wondering whether I could piggy back a 'universal' thermostat on the back of a standard oven selector switch. and use the selector switch to turn on the recirculating fan and light so they are on all the time, as it's designed to be. Can't believe I'm the only one with this problem. I have taken the thermostat out and all looks OK, but probably the contact mechanism is worn inside.
Any ideas appreciated. Its a simple oven with no timers etc and I have the circuit diagrams

 

[Dce]

I found a working solution to this problem myself: When turning off the oven, I don't take it to the end stop. I turn it passed the click when the element and indicator turn off, then further till the light and fan turn off and just a fraction further but not to the end stop. Now the oven element doesn't turn on each time I turn the mains on for some other reason ( eg grill or igniters). I guess there is something wrong inside the thermostat, but this workaround seems OK if not ideal. I've marked a new stop position around the oven dial to remind me. This was easier than making a physical stop for the oven dial.