That's a beast of a cooker - 'Pyrolithic' ?
10mm in a short run maybe. I'm curious to see the size of the terminals on the back of the cooker. If someone was to place insulation on top of the cable inadvertently, during Xmas Day cooking you could have a a house fire. That's a massive draw for a cooker, the largest I've seen was double oven and Induction plate (Range style) and that was at the limit of 10mm @ 60+amps. Bear in mind most/some houses only have a 60A supply!
You may need the distributor to upgrade you main fuse also to 80A/100A.