This follows the successful introduction of a priority parking scheme in the hard pressed area south of the S1 zone. Residents in the area will receive letters with more details but in the meantime, here is a link giving a description of 'priority parking' and here is a Council web page on which will be announced more details in due course (eg proposed consultation timetable). The process is in the early stages.
If you are interested in more detail here is a report from 2011 with the situation in August 2011. (Many of the details are in the appendices.)