Within the devloved administration areas, instead of electing separate MPs and local Assembly Members, have one set of elected representatives able to serve in both capacities. Allow them to participate in Westminster business only on subjects where the relevant devolved assembly has no lawmaking powers.
Why does this idea matter?
This is a solution to the East Lothian question. It also simplifies matters for constituents, by giving them a 'one stop shop' for access to their elected retpresentatives. (The present system can be confusing, requiring people to know when they need to take something up with their devolved assembly representative rather than their MP). It should save money – there are too many MSPs, AMs etc for the amount of business they need to carry out. (Why is it that a constituency in a devolved administration should need at least twice the number of elected representatives as an English constituency, just to get the business of government done?)