The measures aren't the same. The 2m rule doesn't apply, thus more people are allowed in the stores.
Speaking in the House of Commons on June 23, Boris Johnson explained that a one metre gap was permissible, as long as that was coupled with risk-reducing measures.
He said: “Where it is possible to keep two metres apart, people should.
“But where it is not, we will advise people to keep a social distance of one metre-plus, meaning they should remain one metre apart, while taking mitigations to reduce the risk of transmission.”