It is my view that the Scottish Parliament, and the Welsh Assembly, should be made up of those Members of Parliament sitting respectively for Scotland and Wales.
English MPs sitting as such would conducted English business but it may well be that there is a need for an England Act, to formalise English MPs sitting as such, with power to elect a First Minister and to create an English Executive. That English Parliament then would have powers similar to Scotland.
There would, of course, be a need for Acts of Parliament to remove MSPs and Assembly Members, to be replaced by MPs, and possibly also to amend and enhance the Welsh Assembly's powers and status to that of a Welsh Parliament, fully equivalent to the Scottish and English Parliaments.
MPs would continue to serve as they do now at Westminster, working together for the UK, and with their feet on the ground within the devolved Parliaments.