Just landed in BKK from LHR an hour ago from LHR TG917 (renamed TG9179 for this trip).
TG handled the backlog due to the closure of LHR very poorly in my opinion.

Last normal flight out of LHR was Friday's TG917. There were no TG flights out of LHR on the whole of Sat and Sun.

Mon TG911 (TG9119) were strictly for Sat's TG911 pax only.
Mon TG917 was cancelled.
Tue TG911 was strictly for Sat's remaining TG911 pax and TG917 pax.
However, Tue's TG917 (TG9179) was for the scheduled TG917 pax on that day.
That left 5 flights of pax stuck at LHR.
No food vouchers or accomodation were provided, even for premium pax.

Thai's check-in counters were easily the most chaotic in the entire terminal, because where other airlines were sending in extra flights to cope with the backlog (AC for example), TG cancelled flights from BKK instead!