Not Thai?

I've been watching the British detective show "Grace" (which has a super-serious vibe and aesthetics that remind me of Nordic noir), and noticed a possible language flub in Season 2 Episode 2 "Dead Man's Footsteps." I say "possible" because it was in the background at a Thai airport in the public address system, so I had to watch it a few times and even used Google Translate to capture it, just in case I was wrong. But I don't think I was.

I don't speak Thai (except for สวัสดี-ka and ขอบคุณ-ka), but I know what it sounds like because I went there a few times for long stretches, and the announcements sounded like Chinese, possibly Mandarin, not Thai. I even heard the word "Taiguo" 泰国 which is "Thailand" in Mandarin. Like Japanese, 国 is "country," and I know that "guo" is country in Chinese. I already knew how to say "China" in Mandarin (中国 Zhongguo), so when I heard "Taiguo" it stuck out to me, so I kept re-playing the scene and then used Google Translate a few times. I kept hearing various Mandarin words, and 泰国 kept popping up in the app's translation in addition to other Mandarin phrases. So of course, I wanted to bring it up here in my blog, especially because I can't find another post about it online to confirm if anyone else noticed it. 

Since Britain consistently produces excellent shows, I was surprised they wouldn't use Thai in the airport's PA system. It made me wonder how language decisions like this get made in production, and why they'd decide to use Mandarin instead of Thai. Were there any discussions about this before the episode aired? 

If I were working on that show, I would've brought it up; if a show is going to convey authenticity, then they should take languages seriously, especially since this show has a serious vibe.

p.s. the e-book version of my debut novel is still at Amazon, and the price for the print version has been reduced: buy at the Eckhartz Press site.