Hi Marks8

I have found this paragraph from the Good Practice Guide in the Premises section

3.4.2. Laboratories should be designed to suit the operations to be carried out in them. Sufficientspace should be given to avoid mix-ups and cross-contamination. There should be adequatesuitable storage space for samples and records.

The use of the words "suitable", "sufficient" and "adequate" are used such that if storage isn't in two separate appliances, it can be in the same appliance as long as you use clearly defined and labelled sections, and clearly describe the arrangements for storage in your SOPs. Your double fridge would seem to be able to provide sufficient storage as long as your sections are clearly marked and SOPs clearly written.