I tend to check the score before I eat somewhere but I'm often mystified by this 'Scores on the Doors' system. What do the ratings actually mean? Lots of local kebab takeaways have a high rating - 4 or 5 - and more plush places only get a 3. Lots of popular places have 2 or 3, even 1! How are places with a 1 even allowed to continue trading?! What's the minimum you'd look for? Thanks!