“Fixed term, four year Parliaments: dissolution only if government cannot be formed or if Parliament votes for its own dissolution by a two-third majority.”
This is a part of the Constitution that would probably pass with least discussion. Fixed-term Parliaments are mandated in a devolved Scotland by the 1998 Act, and it is broadly agreed in constitutional democracies outside the UK that the power to dissolve Parliament and set the date for the next General Election is not something that should be under the control of the government of the day: it’s one of the powers of the Crown that accrues to the Prime Minister in the UK’s decidedly unwritten Constitution.
Margaret Thatcher used it in May 1983 to call a General Election two years early on the feelgood factor from the Falklands War: John Major used it to not call a General Election that he knew he wouldn’t win until literally the very last minute, April 1997 (and so did Gordon Brown in May 2010, despite Tony Blair’s having set the example of calling an election every four years). David Cameron will probably do the same, unless he starts a small war somewhere for electoral good value.
Looking back at the old Scottish Parliament, it was of course no more representative of the people then the old English Parliament: the Three Estates of the old Scottish Parliament (the lordis of counsall and sessioun) were the prelates (the bishops and abbots: the Catholics were removed in 1567, the Protestants removed in 1688); the lay tenants-in-chief or parliamentary peers (comprising three degrees of nobility: dukes, earls, and lairds – a laird or “lord of parliament” would have been the owner of a landed estate which was not part of a village or town or royal burgh); and the Burgh Commissioners elected by the royal burghs. From 1592 onwards there were also Shire Commissioners, selected by the lairds of the shire, and from 1603, royal office holders: I think the Universities also had parliamentary representation, but I don’t know how that worked. The three Representation of the People Acts in 1832 for England and Wales, Scotland, and Ireland, were the first steps towards making Parliament democratically representative.
The Parliament of Scotland was always unicameral and the collective term used for the members was traditionally the Thrie Estaitis even when there seem to have been four or five. (Mostly from A Short History of the Scottish Parliament.) The representatives from the Royal Burghs were the largest estate within the Parliament, and the 1707 Act of Union specified: “That the Rights and Privileges of the Royal Boroughs in Scotland as they now are Do Remain entire after the Union and notwithstanding thereof”.