The heat element in my 7 year old beko bdvc664w cooker oven has gone but the fan still is working. I want to buy a new part but when looking into my oven to replace I think I would need to unscrew a cover over the fan and element. My problem is the screws look to be rusted and none of the screwdrivers I own work. Am I in the right place or is it from the back?