Before you do any unneeded work,
What are the cooker and hob rated at?
There should be a plate or sticker on them somewhere

What is the distance from your fuseboard to your cooker?

From the board to the cooker no more than about 10m.

Bob

Ding,

Perhaps you can teach us using this real life example?
Please show all your working out  

I would prefer to see two circuits installed - one for the hob and one for the oven.  This because the oven is on the large side.  Two single gang sized 45amps isolators do not look bad side by side.

Assuming the 6mm cable is not in thermal insulation in a loft or wall (60/70/80 house typically) and is either run in the empty floor void, and buried in a solid wall or run in an empty stud wall, then the cable is rated at 47amp (Method C).  You could therefore have a 45amp breaker, 45amp switch, and 6mm cable feeding both appliances.

If the cable is in a stud wall with insulation, or run through a loft with insulation etc, you would need to take due account of this.  The cable would then only be rated at 35 or 34 amps for an insulated stud wall and above a ceiling with 100mm of insulation respectively.  A single 32amp 6mm circuit for each appliance would be fine.

BUT.

How about diversity for both appliances?

The regs allow you to apply diversity to the full load of a cooker.  I do not have the OSG on hand to check what the percentage of the second appliance is, although I think this only complies in commerical.  So, lets assume 11kw of load as 'a single appliance'.  

11,000/230 = 48amps.

The first 10amps, plus 30% of the remainder would give a design current of just 23amps.  In reality this is a tad low, but makes your 45 circuit with a 48amp load look fine

Bob,

As Lec has said you can feed them both from your one 6mm

I did consider lots of thing's....

Then thought to myself,
“that's a bloody big load for a 6mm I wonder how long the run is”

I'm on my way....where's my pencil?  

You want me to ''Rock down to Electric Avenue?''