Didn't they hold a referendum on an alternative voting system and it failed? I'd moved away by that time, but I seem to remember they basically chose a bad and confusing system to make sure it didn't pass.

MMP seems to work very well where I currently reside and it wouldn't be too confusing to add it to the British system, basically adding a party vote alongside the local MP vote and then taking MPs from the party lists to make it proportional.