I am just about to disconnect our old oven and have found the live and neutral and am fine with how they connect but am a little unsure as to how the earth will connect to the small earth tab on the new oven.

You may need to get a wire connector to install on the ground (earth) wire, so it can be connected to the terminal connection point on the new oven.

If one wasn't provided with the oven, some do this as a service, just look at the ground terminal or in the bag with the instructions, etc. for one. If not, you should be able to purchase one, you'll just need to get one that fits the wire, so knowing the gauge of the wire (either Awg or Kcmil size) will make this easier to get the right connector size.

I recommend that a ring terminal be used, so in the event that the fastening screw might loosen, the ring terminal will not fall off the contact point, whereas a fork terminal could and can come off much more easily.

Not having more detailed info about the brand and where you're located, makes further possible solutions difficult to provide, since Fixya doesn't require requestors to provide any info on what country they're in, etc.

Nonetheless, I hope you find this Very Helpful and best regards!

The copper wire from the cord should go to the ground(or earth) screw or post on the stove.It should be around the terminal block