I’d like to see on the ‘Block gambling transactions’ screen a little summary such as ‘In the last 6 months, the following transactions were classified as gambling related…[list]’: I suspect the National Lottery is classed as gambling, but not 100% certain.
You missed a step out on how to enable it! 
After clicking settings you need to click “Spending Limits” then “Controls”! 
Awesome feature though! 
I think the gambling block should have a configurable limit per month rather than simply an on/off block.
Sometimes you might not expect a major sports event on which you’d like to gamble and by the time you realise the block and 48 hour delay will make you miss the game. A limit would instead allow you to gamble should you want to while still preventing you from betting more than you can afford to loose.
Great news, I can personal say the feature works! Not only as a great blocker, but as a reminder/‘deterrent’ for anyone who might feel they have any gambling issues, or not want to even try!
Can I also highly recommend the following site : https://www.gamstop.co.uk/
It has a very fast growing list of online gambling sites which will automatic self exclude users by signing up to the page.