It can be tricky to make good supplier choices.
Within the government it is more or less standard to provide directly all documents and certificates during the registration, so at the tender stage. If these are not provided during the registration, that means an instant knockout. Herewith you control as commissioning organization that the enforcement afterwards in any case is a lot easier. The products supplied have a CE-certificate.
There only needs to be a check to see if the products supplied are indeed in conformity with the certificates. This is mainly in the field of inspection agencies for validating use permits for fire and evacuation systems.
The latter is still an important issue. It appeared in other disciplines that after validation still other products were delivered than according to the enclosed certificates. This obviously is malpractice, but unfortunately it happens and therefore a client is only secure if the whole process, from quotation till completion, is covered by a guarantee. Only thus can he preserve for future claims. To remain in legal terms, how can you demonstrate that you have done everything to make sure that you have received the right products and the right commissioning?