Can my stoves 720EF electric double oven be replaced without having to replace the hob?

SOURCE: Stoves 720ef electric double oven not working

According to the circuit diagram on page 31 of the handbook, power for the ovens passes through the clock. The power feed is direct for the actual clock but via a seperate Thermal Cutout for both the top and bottom ovens. I think it is highly unlikely that both Thermal Cutouts have failed at the same time. I would try turning the power off totally to the oven for a while and then turning it back on, set the time and ensure the oven is in manual mode. As the top and bottom ovens have seperate controls after the Programmer and both are not working, it has to be the programmer that is not extending the power through to the rest of the oven.

SOURCE: looking for replacement rotary switch for stoves

Try espares.

SOURCE: How to replace the grill element in a Stoves 720EF

1) Isolate the unit by turning the power off at the main switch.
2) Remove appliance from housing unit.
a) When handling the appliance care should be taken to ensure the outer frame trim is not damaged.
b) The appliance is secured into the housing unit by 2 screws through the top corners of the front frame, open the doors and unscrew the 2 corner screws.
c) Grasp the bottom of the frame, pull forward and out onto a suitable surface.
3) Unscrew the top and rear panel securing screws and lift the panels clear.
4) From the rear of the appliance, pull off the 4 (top) grill element leads and the earth lead.
5) From inside the oven unscrew the 2 screws from the grill mounting plate.
The above is from the Handbook. I assume from point 5 the element is then free to be removed. reverse the procedure to fit the new element.
If you want a copy of the Handbook, then I will need an email address for you.

SOURCE: Hello, I am looking for

Yes it is. All I need is an email address and I will send you a copy.

SOURCE: Having taken the oven out to fix a problem with

Both the top and bottom oven will only work if a time (any time) has been set on the clock. Setting the time operates a contact to switch the power through. The only exception is the grill. This will work even if the time has not been set. So if the oven controls/lights and heating work, to me it means that the clock/timer is half working and the only thing that isn't is the display.
I haven't had the clock/timer to bits but a fellow blogger has said that in some timers there is an electrolytic capacitor that controls the display. When this fails as they are renowned for doing, the dispaly mal functions. If there is one then Maplin have some - VHR41W/43W and DT64U depending on value etc. Let us know how you get on.
If you need a new clock/timer they are around £80 from espares.