New help page section: "What information can I request?"

[RichardTaylor]

New section, perhaps for the top of:

https://www.whatdotheyknow.com/help/requesting

Inspired by tweet:

I've always been intrigued... how do you know what FOI requests you can make? i.e. how do you know what data points the Dep of Housing has that you can request, if they're not in the public domain?

https://twitter.com/Sally_Brown/status/1452922398555136006

As for what we might put in that section, there's perhaps some overlap with the answers we have to the question: "I’m not sure which authority to make my request to, how can I find out? "

Suggestions:

• Look at the "publication scheme" is a technical answer, but it's not likely to be useful so we probably shouldn't mention that.
• Just ask for information you expect to be held by a public body and don't worry might be a good answer. Note the duty public bodies have under FOI to provide advice and assistance, and note that a "not held" response might still be noteworthy and actionable.
• Many FOI requests are for material mentioned in published material, on a public body's website, in other FOI responses etc.
• You might request an updated version of information you've seen released previously.
• You might ask for local information which you've seen released by a similar body elsewhere.

[garethrees]

There's a generic version of this, as described above, but we could also add advice specific to classes of authority via https://github.com/mysociety/alaveteli/issues/387 and https://github.com/mysociety/whatdotheyknow-theme/issues/442.