"I think it would be very difficult to find a suitable investigator who had fully followed all of the Covid rules at all times."

Well I've followed the rules at all times. I doubt that I'd be an independent investigator of a Tory party that I already know to be corrupt. So I'm not suitable, but there will be millions like me, and many of those would be suitable. Whoever it would be, it wouldn't be one of the Downing Street in-crowd, that's for sure.