Anyone done anything about modifying the BA boot lining?

Unfortunately, the carpet has been moulded to conform to the split level boot (sunk where the spare tyre sits), and sunk even further around the timber spare tyre cover (which creates small, irrelgularly shaped, drops in the carpet).

The end result is the ability for taller but not very wide items to fit in the boot (apparently), but it is difficult to put multiple flat items in the boot (such as suit cases or boxes) side by side as they cannot sit flat.

I had thought before I bought the car that I would simply add a plywood bottom on the boot under the carpet (which would fix the irregular problem, but not the split level problem), but the moulded carpet makes that solution difficult.

What is an AU boot/boot lining like? Body is similar....