in my department we have to submit a 5000 word report after 8 months. that is not the upgrade from MPhil to PhD yet, but rather just a "first year report". The real upgrade is usually between 15 (which is considered as extremely early) and 27 (very late) months. in order to upgrade we have to submit 3 more or less finalized chapters (including at least one "substantial" chapter, i.e. including data & analysis) and detailed outlines of the contents of all other chapters, plus a timeline for finishing.
that's all for full-time students. parttimers have different schedules and deadlines.