Potting rupicolous Laelia sanguiloba - advice PLEASE

[Orchid killer]

I have just purchased my first true rupicolous laelia - Laelia sanguiloba. I was expecting to receive the plants bare rooted or in an inorganix mix.
Instead it has been potted in a bark mix !!! I’m not sure what to make of this.

Anyone out there in the big wide world who can advise me my next step. I received it with a new emerging shoot, however should I take it out of it bark mix? Or leave as is for the time being?
Because of the new shoot, I was planning to pot it up into an inorganic mix of rock, charcoal and crushed macidamia nut shells. Is this a good idea?
And the pot – can I use plastic pots or is clay recommended?
Lava rock and rock wool is not available for me, so will substitute it with macadamia nut shells which is very hard and take years to break down.

All commends and advice most welcome.