The law is against 'unfair business practices', but the Competition and Markets Authority took action when businesses raised the price of hand sanitizer when there was lots of demand in 2020.
Now businesses generally can't make big price shifts due to increased demand or constrained supply.
The CMA investigated whether firms were stockpiling hand sanitizer and making excessive profits on it by creating artificial shortages, at a time when hand sanitizer was being promoted as an essential good. As your link acknowledges, they then promptly closed all the cases without further action.
Paying more to suppliers to import a particular non-essential foodstuff in a year in which most food prices have risen is even less likely to invite action.
If fuel prices can legally double overnight and fuel vendors make larger markups as global prices stabilise without the CMA batting an eyelid, it's quite hard to pretend that the CMA is the obstacle to us having access to the same food supply chains as European supermarkets...
Except that isn't a law. Although if they were all shown to be acting in concert, not buying tomatoes in order to get a better price. That would be illegal.