Mystery solved! I've just picked a 2019 Audi Q3 which came with a bottle of gue and a tyre inflator instead of a spare wheel and tools. If anyone is interested in getting a spare wheel and tools then the bits you need to source are the following...
5Q0-803-899 Wheel Bolt and clamp. This fits the socket shown in Brian's picture above. If you already have the subwoofer speaker in your car you will already have this.
5QF-011-031-C Jack plus 5Q0-011-221 Jack crank arm. (The crank arm is the Jack handle and it is sold separately!)
8N0-012-219 Wrench
83A-012-109-H Audi Q3 Foam tool compartment for spare wheel.
83A-601-010-A or 5QF-601-027-B Spare wheel. It is a 4J x 18H2 ET 28 wheel fitted with a 145/85 18 Tyre. (Same spare wheel for all wheel sizes)
Don't forget to transfer your tools from the old foam compartment to the new one! When finished your new spare wheel and tools take up exactly the same space as before and you can still put your boot floor in the lower position.
