For anyone curious, the issue has been resolved. A repair tech replaced the control panel as well as the temp sensor. It’s fixed, but can’t be sure which part was (or if both parts were) bad.
Thanks. I have it posted in three other forums too. Once I get it figured out, I’ll update all threads with what happened. Thanks for the links, I’ll post it onto those two forums as well.
What I provided is the model number as listed on the sticker inside the oven door. I know of nowhere else to look for this mysterious 85… number. Keep in mind also, this is a model sold and used in America (not sure if the UK models are numbed differently maybe).