Pretty straightforward to adjust it from a majoritarian system to a proportional system ...
Under the section on Referendum on voting systems:
- amend clause 2a to read Single Transferable Vote system
- amend clause 3 to read Single Transferable Vote system
- delete clauses 4, 5 and 6; and replace with:
In this section “Single Transferable Vote system” means a system under which:
- The number of Members of Parliament to be returned in a constituency shall be either two, three, four or five, as determined by order.
- Different numbers may be determined in relation to different constituencies.
In each constituency in which there is a contested election, a poll shall be held at which each person entitled to vote as an elector may vote by marking on the ballot paper:
- the voter’s first preference from among the candidates to be Member of Parliament, and
- if there are three or more candidates and the voter wishes to express a further preference for one or more of those candidates, the voter’s second and, if the voter wishes, subsequent preferences from among those candidates.
Then re-number remaining clauses as appropriate!
Its certainly not rocket-science.
Any bets on the first MP to table such an Amendment??