Good morning.
I begin by saying one opinion of mine: a lot of quality consultants or quality auditor are too theoretical men. They forget that companies have to bill and make profits, first of all. And they often forget that certifications and ISO standards are private rules not laws neither public regulations.
Finished introduction.
What do you think about a supplier (certified) which does not allow customers to perform audits?
OK, it's not "fine" but a customer is not a public inspection body: if a supplier does not want to be audited by customers, a customer cannot force him.
The only thing it can do is stop sending orders (if it can)
Am I right?
It is about your wishes.
Need the relationship with such customer? because you have important profits? well , you need to allow to be audited under
a reasonable basis, say 1 or at most two yearly, but it depends mainly of the customer´s needs.
If you reject the audit, for sure , this customer will try to look for another supplier, as simple as that.
On the other hand, if this customer place you very few work orders (say 5 at year) very little profit, and don´t see a
good relationship in the near future and beside of that want to audit you 2 or three times a year, then....
You might start to reject some audits.
Hope this helps.