A company's financial year is determined by its accounting reference period, which runs from incorporation (ending on the last day of the month of the first anniversary) and then annually from the accounting reference date, with the directors able to end the financial year up to seven days either side (section 390). The accounting reference date may be altered by notice to the registrar (AA01) subject to the restrictions on extending more than once in five years and beyond 18 months (section 392).
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.