Eeee! Blind b*****r Me!!!Now to me that looks like the space over a cupboard. Its the one to the side with 65mm from hob to top of oven you should be looking at. I may have that wrong.
The 65cm is the distance from the hob to the extractor or cupboard above it
That would definitely be to stop heat passing down, especially if over a cupboard unit.how does the heat resistant board fit into the equation
Ooophs 65 mm deffo a typo I take it you have fitted the same model did you have any issues when fittting ?