See http://paperdestruction.org/ “FRAMEWORK FOR THE DESTRUCTION OF PAPER” for a very detailed treatment of this topic. The short answer is that if you have a validated process to certify copies, you do not need to retain the paper. In fact the MHRA made the following interesting comment at a recent TMF Summit”
“11. Can you destroy paper if a certified copy has been created?
A certified copy can replace an original paper which can then be destroyed. If the original has not been destroyed, the MHRA may ask why. If you certify copies and then don’t destroy the originals, are
you confident you have a certified copy because what is rationale for keeping the paper? Not necessarily a finding, but would need explanation on why you would still be keeping the paper originals.
Inspectors may want to look at the paper. ”
See https://tmfrefmodel.com/wp-content/uploads/2018/12/UK-MHRA-q-a-TMF-Summit-2018-12.pdf for the summary of this MHRA Q&A session.