LGA1972- asap; that 6-month thing is a red herring.
(6)A casual vacancy among parish or community councillors shall be filled by election or by the parish or community council in accordance with rules made under [F4section 36 of the Representation of the People Act 1983] [F5in the case of a parish council or, in the case of a community council, made under section 36A of the 1983 Act].
(7)Where under this section any question is required to be determined by lot—
(a)in the case of a contested election, the lot shall be drawn by the returning officer immediately after the question has arisen; and
(b)in any other case, the lot shall be drawn at the next meeting of the council after the question has arisen, and the drawing shall be conducted under the direction of the person presiding at the meeting.