Having a tizzy because I asked if Skype is still a thing?? I haven't used Skype for probably 8 years so it was a genuine question as I thought it had been beaten into submission by Zoom, MS Teams, Google Meet etc.
Anyway, if you use AIS you can use the 003 prefix (rather than 001) to get cheaper international calls. 159 baht gets you 40 minutes of call time to the UK. https://www.ais.th/003/en/
DTAC do a similar thing with 004 but they don't say what the rates are. https://www.dtac.co.th/en/idd.html