While we're at it let's update the commons too:

Abolish the whips' offices
All votes in parliament are secret
You can only vote if you attended the debate
Voting in elections would be compulsary but with the option "None of the Above".
No new laws or amendments can be made if the party (or parties in the case of a coalition) has less than 50% of the votes cast.
A petition of a suitable size (say 10% of the electorate) can force a general election
No minister can serve in the same position for more than 5 years.
No MP can serve more than 15 years consecutively without a break of at least 5 years.