Single Electric Cooker to Hob and Double Oven

I am wanting to install a separate electric hob and (possible double) oven. There is already a fitting (cable) for a single stand alone oven. What do I need to do /or check to make this possible? Thanks in advance.

You say there is already a "fitting" for a single stand alone oven. What do you mean by fitting? is this a socket or a cooker outlet plate switched via a cooker control Unit?

The next thing to check is size of cable used in mmsq i.e. the cable has to be LARGE enough to take the load of your hob (and potential oven). Which you also need to check it will be quoted in Kw

Next is the length of cable run from your cousumer unit to the cooker as voltage drop needs to be taken into account

Also is the cable in conduit as this derates the cables current carrying capacity

There are quite a few factors as you can see

Finally its notifiable work to the LABC local authority building control office so you have to inform them if you do the work yourself and pay the fee and pay for someone to inspect

If your confident then go for it so long as you inform the LABC. If not get a spark in.