What the law says about the Annual Return?

What does the Law say about the Annual Return from Cambourne Parish Council?

As the NALC puts it:

2.33. The authority needs to ensure that the accounting statements are signed by the RFO and approved by the authority, by the latest date in order for the RFO to comply with the duty to commence the period for the exercise of public rights so that it includes the first ten working days of July. 

This hasn't happened. Cambourne Parish Council IS acting illegally.