You will need European country Competent Authority (CA) approval before you initiate a clinical investigation in the country under their authority. In my experience, the expectation is that the non-clinical MDD/AIMDD Essential Requirements need to be met before you start the study. From my perspective, this means you will need to have successfully completed design verification including non-human safety testing. Proof of this typically needs to be submitted to the CA.
The clinical study is basically a design validation study, so I don't think you would be expected to have completed design validation before you initiate the study.
Regarding process validation, other than having completed sterilization validation (or batch-release validation) and perhaps sterile barrier heat seal validation, I do not think there is an expectation that "process" validations would be completed before a pre-market clinical study is initiated.
ASIDE: For USA clinical investigations under an IDE per 21 CFR 812, you are specifically exempted from compliance with all parts of 21 CFR 820 except for 820.30 (design controls). I would apply the same general philosophy as described above.