It is my opinion (sorry for having one) that electrical installations in rented property should be subject to a 'stricter' PIR than private households. Three reasons (all similar) - first to safeguard the tenants, second to safeguard the landlord (the client) and third to safeguard the inspector.
I thought all PIR's were to 7671?
Or when you say "Stricter" do you mean something like this?