Sorry, it keeps me thinking.
the independence of audit is more than questionable
Yes it is.

It works as follows: External auditors are usually freelance and work with many consulting firms and one Notified body. Consulting firms have different relationships with the NB (eg ownership, equity, etc.), jointly organize trainings, meetings with clients, consultants and determine possible future auditors. I met with this person, and not once.
Regards Jagoda