Just the basic, no-status membership but am not sure what my dad is (if the person booking the ticket makes a difference). Can I still get into Arrivals lounge?

Too bad about the long-haul flight. I will still get to see the magical lounge on the way back to Thailand (this is always a big deal to me because it's rare) since that time I will be on a departing business-class flight, but I have more time to kill on the way out.