UK online casinos operate under strict rules from the UK Gambling Commission,...

https://front-wiki.win/index.php/How_Do_Casinos_Recover_the_Cost_of_Bonuses_with_Wagering_Requirements%3F

UK online casinos operate under strict rules from the UK Gambling Commission, which set limits on payout rates and player protections. For example, many slot games are designed with a return-to-player rate around 96%