After no responses from a couple of garages around my area, I decided to call Honda dealership and got through to their Servicing department.
They confirmed that that Mk2 Jazz is NOT susceptible to easy Cat theft! (Hurrah!
)
They explained its because the cat is near the engine area, so its not easy to steal.
The Mk1 however, was very vulnerable.
Having said that, they have no official solution for the Mk1 models, except to suggest you try calling around local garages to see if they can help fit the cages that are advertised online.