That's how our place does it.
Probably not breaking any laws, as the number of pedantic jobsworths we have who 'know their rights' would definitely have kicked off by now, not to mention the union lot who are ever-ready to pounce on the slightest slight against the workers...
This is the thing though i think it is against the law
https://www.gov.uk/rest-breaks-work
Daily rest
Workers have the right to 11 hours rest between working days, eg if they finish work at 8pm, they shouldn’t start work again until 7am the next day.