I’m picking up a second hand Carrera Luna for my daughter. I’m a big fan of her riding a lighter, rigid bike so plan to swap the bounce forks for rigid until she is bigger/better. Any suggestions where to pick up sensibly priced, compatible forks for 24in wheels?

Depending on tyre size, you could get away with a CX fork with ~400mm axle-crown length. Kinesis do an aluminium one for reasonable money.
There may be some Chinese alu or carbon options on ebay.

Or get an old school SID or Mars and lower it as much as possible.

I put a 26″ Recon on my sons 24″ bike, worked great and only 1.6kg

What size steerer is it?

What size steerer is it?

No idea I’m afraid. Haven’t got the bike yet and not able to find a good spec on internet