Freedom of Information (FOI) requests: multiple questions or single question per request? In England and Wales at least, Freedom of Information requests are a legitimate research technique to use for obtaining data on occasions when (a) they are applicable, and (b) other avenues have been exhausted.

If a researcher wishes to obtain answers to multiple questions, or to obtain multiple different datasets, should (s)he submit:


one FOI request providing a clear list of the requested items; or
one FOI request per item?


I would be especially grateful for links to relevant advice from trustworthy sources, and for advice from academia.stackexchange members who have either made or received FOI requests.
Under a single request, you can requisition multiple data that are related.

As a guide for FOI officers (the people who will process your request), the State Government of Victoria gives this gloss:


  Practice Note 4: Multiple Requests for Access
  
  Summary
  
  Multiple requests arise where a number of applications for access are made by
  or on behalf of a person at the same or within a short period of time
  (e.g. within 2-3 weeks).
  
  If there is sufficient commonality between the requests, they can be
  considered as a single request to determine whether it is a
  "voluminous" request under section 25A(1).
  
  Each request should otherwise be treated individually, in the usual
  way.
  
  If it is not reasonably possible to notify a decision to the applicant
  on each request within 45 days, subject to the FOI Act, take practical
  steps to consult with the applicant about priority of requests and to
  possibly reduce their scope.
  
  
  Note: references in this Practice Note to sections are references to
  sections of the Freedom of Information Act 1982 (Vic) ("FOI Act")
  unless otherwise stated.
  


I have experience requisitioning such data (i.e., warranted by FOI) from commonwealth government law enforcement agencies.

The specific protocol (e.g., email, web form[s], and/or paper form[s] to submit) for filing a freedom of information request will depend on the agent or agency to whom you're submitting it.

Typically, the agency will ask you to state the specific data you want under a single subject heading so that the scope of their response is appropriate to your request.

See How to make a freedom of information (FOI) request by the UK Government Digital Service here: How to make a freedom of information request