After many hours spent researching, I have come to the conclusion that the following three mushrooms belong to the species Lentinus polychrous (syn. Lentinus praerigidus) and although they have different Thai names (perhaps local names), they are the same mushroom:

HET KRADANG (เห็ดกระด้าง)

HET LOM (เห็ดลม)

HET BOK (เห็ดบก)

Could someone possibly confirm this?

Also, for some reason HET BOK is often written as HET BOT. Perhaps my Thai script is incorrect.

Thank you for your help.

I believe it should be HET BOT (เห็ดบด), not BOK.

And Wikipedia suggests that they are indeed the same mushroom. See https://th.wikipedia.org/wiki/%E0%B8%A3%E0%B8%B2%E0%B8%A2%E0%B8%8A%E0%B8%B7%E0%B9%88%E0%B8%AD%E0%B9%80%E0%B8%AB%E0%B9%87%E0%B8%94

Dear AyG,

Thank you very much for checking that up and also for the link. That's a relief.

Your Thai script for HET BOT is correct.

Much appreciated.