Just measured the space under the hob, don't know why but after installation of the hobs the remaining height is 1cm short for the required height of built-in oven. If I remove the bottom shelving board from the kitchen cabinet, and build a wood frame/shelf on the floor supporting the oven, would that be okay? Should be more sturdy than the 18mm MDF board supporting the oven but not sure if there's any rules that not allowing this?