Full Panasonic service Manual, as described, no problems
Text excerpt from page 12 (click to view)
Baking trays and dishes For your safety
Never place cooking dishes, trays and so on over the oven burner. This will damage the cooker as well as the cookware and possibly the floor covering underneath the cooker.
Leave a gap of 13mm (Â½") between all dishes and the sides of the oven so the heat can circulate properly. Do not push dishes too far back as food will burn if it overhangs the burner flames.
For the best results from the oven we recommend that you use a baking tray which is 310mm (12") square. If you use a tray or tin which is larger than this, you may need to turn it around during cooking. Place single dishes on the centre of the shelf. You may need to turn large items around during cooking.
For best results we recommend open roasting using minimal fat or oil to prevent splashing. It is not necessary to cover meat or poultry or wrap food in foil when roasting as this restricts the circulation of heat and will lead to extended cooktimes. If you are using a roasting bag or cover chicken breast with foil, be prepared to allow an extra 10 - 15 minutes for each 1/2kg (1lb). When cooking large items such as turkeys, the use of foil may be required to prevent the breast becoming dry before the rest of the bird is fully cooked.