We had to address this with our Spitfire, which has very similar locks. We did have an ignition key but no others.
First off, none of the lock barrels had key numbers that we could find.
Secondly, if you have a selection of keys and the barrels out, it is possible to select a best fit key and then swap tumblers around to improve it. If you have extra locks for a greater selection of tumblers, it helps. Tumblers can also be filed down.
We managed to end up with a one key for the ignition and one more that fitted both doors and the boot. The boot lock mechanism was a mixture of Rover 25, MX5, with a Triumph barrel......
It's simple engineering - no magic or witchcraft.