Regulation is not an endorsement
A Gambling Commission licence provides a regulatory framework for serving consumers in Great Britain. It does not certify that a casino offers good value.
Check the licensed entity and domain, then inspect withdrawal conditions. An authorised business can still require identity checks and investigate transactions before releasing funds.
Read the game before funding it
A slot's advertised return describes long run mathematics, not a session forecast. Different versions of similarly named games can also use different return settings.
Look for the rules within the actual game window. If you cannot establish the stake, feature purchase cost or return setting, leave it unplayed.