your wholesaler/supplier. I believe so longs as it is something that will act as evidence to prove the CD entry of the drug that you made in the appropriate book. Otherwise people would be making up values with no idea on where to trace the origins of the controlled drug.
Check MEP35 , only schedule 2 and 5 need invoices kept for two years. The home office has advised that patient returned and pharmacy stock CDs should be destroyed but which schedules ? 2,3 and 4 part 1 ?