Help needed please. The grill elements in my top oven go to full heat no matter what setting I put it on. They will both work independently, and together, but still with the same fault. They both seem to work ok on the normal oven setting but have yet to have them checked with a ‘meter thingy’. From reading other posts am I right in thinking it could be the grill regulator (6204034) and/or the main selector switch TBH, (6201720) don’t really know what TBH means! Simmerstat seems to be mentioned a couple of times but I’m not sure if this relates to the same problem. Would appreciate any feedback Thanks in advance