There is no requirement for referenda to be held concurrently with Council elections.

Indeed, all the referenda to date have been about changing the rules before the next election.

EDIT: So when SD69 says:

I don't know to what he is referring. There are two references to "1 month" in the Council election rules:

• #9: The election date must be publicised at least 1 month in advance of the election.
• #12.2: The referendum options must be debated for a minimum of 1 month prior to the referendum.

It is therefore the choice of the Council as to how long the referendum debate and council hustings may be (with restrictions, see also points #1, #2 and #8)

My reading of point 12.2 (and, since I wrote it, I think my reading should count for something - although I'm going off my thoughts now, not what they were 3.5 years ago) is not the same as SD69's. When he says:

This is not debating the options. The debate of the options has only started today. There is no proposed referendum yet, and so there's a month to form the question, and its options. I may be wrong, other opinions may vary.