happy to share: eucompliancepartner.com they helped me a lot with every aspect of GSPR inlcuding warning labels and files needed. The prices were the cheapest compared to any others we have found. Im sure they can answer ur questions.
For UK Responsible Person, and EU Authorised Representative (same thing), FastTrack cover both territories in one go for a single fee, rather than having to register separately. Happy to recommend https://wearefasttrack.com/