Cooker Isolation switch or Cooker control Unit needs to be accessible for ease of isolation purposes. a maximum of 2 metres from the appliances and above the worktop is the best place, behind the appliance is not suitable. The The control must not be fitted directly above the hob, at least 300mm to one side is the recommendation.
Both appliance can be run off the same circuit providing the calculations are made for MCB and Cable.
A spur can be used if it is a fused connection unit a switched unit would be best as this will allow isolation and again isolation above work top is recommended, this can only be done if the appliance rating are low enough to take a feed from the power/socket circuits available.
Other than that a separate circuit needs to be installed
Out of interest what rating are the appliances? As this will determine the size of MCB/Fuse and cable size to be used.
This is in the kitchen so it does need to be notified to building controls if a new circuit is being installed and or new accessories, MCB.