I think that another clarification about proroguing is needed. Proroguing is not merely a parliamentary procedure. It is part of constitutional law. It was a power that the monarch had when the first parliaments appeared, to call and then dismiss (prorogue) parliament as and when he (or she) determined if a parliament should sit.
https://www.nationalgeographic.co.u...amatic-history-prorogation-british-parliament
"Proroguing was first used in the 15th century. Back then, governments were usually summoned for brief periods, then dismissed at the monarch’s whim. Those early parliaments were designed to approve taxes and royal expenditures, and were given the monarchical boot when they were done.
Over time, though, parliament gained more power, and monarchs started using prorogation to put them in check. For example, in 1759 Elizabeth I prorogued parliament to avoid public debate of a potential suitor, Francis, Duke of Alencon. Other monarchs used the tactic for good reason—in 1608, for example, James IV issued a prorogation in response to a typhus epidemic in London."
Proroguing is a common law that is part of the UK's Constitutional Law.