I am installing a 600mm Diplomat oven in a standard under counter oven housing. There are virtually no instructions on how it is mounted in the housing (either with the housing or the oven) but a useless diagram showing the oven just slotted into the gap. I have worked out the stability screws for myself but it looks to me like the oven needs to be raised by around 18-20mm to be flush with the top of the adjacent drawer fronts and for the bottom panel to fit properly. Do I just put a piece of 18mm board on the shelf and slide on top of this? Anyone come across this before? Thanks