You are correct on this that it doesnt have a control board. As this model is controled by switches not a control board so that wont have blown.
As to reverse polarity again as you dont have a control board then that wont have caused a problem as all revers polarity will do is stop some parts from working. It wont cause anything in this to fail.
You dont really say what the oven has down wrong other then the smoke from the grill. If this is the only problem then that wont have caused any damage as this is quite common in single ovens as grease an fat splashes onto it so when you turn the grill on it will burn all that off first and smoke while it does it but then it should clear.
If that isnt the fault and the oven is not working then contact Beko if its faulty as they will be the ones that need to call out and fix it not the supplier as they are giving you totally wrong infomation as you dont even have a control board.
If you need anymore info just get back to me.
Arrh sorry just read a bit more on the fault at the bottom were you said it was dead. If it is and the power is fine to the oven then its possibley the thermal cut out inside which is a small thermostat. Again reverse polarity wont have caused this to fail on these so the suppiler is wrong to say that.
Excellent Daniel, Just as I thought. Young whippersnapper that thinks all old school guys are all morons! I meet them a lot. I'm going to keep your excellent answer under my belt as ammo if they get stroppy. I have already paid £90 extra for a replacement. So much for warranties, eh! By the way, I had the same fault on an old Diplomat oven and replacing the 120 C rated safety cut out with one I had handy at 125C and the problem is cured.
Once again many thanks. I have rated you top marks.
Best eleven pounds I have spent for ages.
May you have many perfect children.
Your very welcome. I was just glad i was able to help you on this.
To rate you just need to click the smiley face and that will do the trick.