I have been through SC vetting. Thought DV was just too much and worked for a big corporate at the time.
There is no way you go through the vetting and no one is allowed to tell your masters the answer. Otherwise what is the point of it? Certainly Sir Ollie shouldnt be going into the finer details of the report itself but Mandelson didnt pass - with hindsight of course he wasnt going to with all his previous contacts. Sir Ollie then decided to not tell Starmer the result - after all he was only the PM!
The Civil Service are known to keep their bottoms covered. Why would Sir Ollie decide himself to pass Mandelson anyway and not tell anyone?
It all stinks to high heaven along with the 'stolen' phone. Funny bearing in mind the importance of the phone that it hasnt been found. Its all wiped of course.