The UK did not exist in 1652. It was formed by the Acts of Union 1800. In 1652, England was (briefly) not even a monarchy - that is what Commonwealth refers to here, not the modern one.

Urquhart was imprisoned from 1651-1652 for fighting on behalf of Charles II, who was King of Scotland until his defeat in 1651, and trying to take the English throne. He didn't get the English throne until 1660.