The BPI are not 'official' anything
There's that problem again, the BPI for all the fine sounding name are not an official anything and should not be accompanying the police on the raids. They are a civil third party with a vested interest in the outcome of the raid and with no power to perform raids independent of the police.
The only people who should enter a property in a raid are the people authorized by the court to ensure the evidence is cleanly obtained without tampering. If the BPI didn't have the power to enter during the raid they should not have entered under the cloak of a police raid as pretend policemen.
This goes for BBC camera men too, they go along with a raid, and enter property, the policeman says "Police we have a warrant let us in" and the owner lets them in. However he is deceived, the truth is "Police and BBC Cameraman, with a warrant for the police only" is the reality.
The court didn't authorize the cameraman, he goes in pretending to be a policeman.