If I've understood what people have been saying:
so a single 10mm2 (which you run everything off) or10mm² would be plenty for that.
2 by 6mm2. I assume you'd split the sockets between these 2 cables.Another possible option may be to run TWO 6mm2 cables - one for oven, one for hob - if your electrician hates working with 10mm2 (as I do!).