Re: the £25 shorts: aren't there XL or 2XL sizes for men's clothes in Lazada or Shoppee? I've seen the Decathlon store here in PH, they have sizes up to 3XL. (3XL in "Asian" size, I guess.
(btw I know that Mendy is a tall Caucasian guy, so might have difficulty getting clothes in TH or even via Lazada or Shoppee, which usually are sourced from China)