Whist not speaking for Gerard Planche, who is the chap who arranges the "Corvette Corale" at Le Mans as a private enterprise, it is extremely unlikely that there'll be an infield parking space - the ACO just does not accommodate car clubs in the infield, and really never has. (Gerard managed to get a trackside location once, due to a cancellation I think) The track interior is reserved for companies and corporate hospitality, like it or not! The "Corale" is outside the track, towards the Porsche curves.
The Le Mans Classic is the event for car clubs and plenty of them have areas within the circuit for the weekend. Unfortunately, CCCUK has never been one of them.
Ah! That makes a difference! Yes, You can buy tickets in the ACO's membership area - not a great spot it has to be said.
Other alternatives, be in/join a club that has an area; come with one of the "Classic Car Travel" companies, which often have their own areas; convince someone in CCCUk to finally get its own area organised.
As this years event was cancelled due to Covid, and, the Peter Organisation that runs the classic are only very reluctantly giving refunds, you may find that a lot of the available spaces for 2021 are already filled. But, normally the ticket applications are sent out to, or are available to clubs around November time. Places need to be booked and finalised usually by Christmas.
If you opt for the first alternative above, now is the time to get in touch with the companies. Try, for example:
Classic Grand Touring (expensive)
Scenic Car Tours
All will also arrange hotels/camping etc as required.
Others are available.
Be warned, hotels are at a premium here for any Le Mans events, so booking very early is essential!