Don't suppose it really matters in all honesty, the continual low turn outs at varying levels of polling show the publics utter disillusionment & general feeling of alienation from the politicians, parties & policies enforced upon them throughout the land.
Until everyone eligible to vote partakes there will be no true representation of how people truly feel about the style & art of government administered upon them. Far too many turn away because they feel they aren't listened to & until that root problem is sorted no matter what form of voting is in place there won't be a true reflection of the populaces attitudes or willingness to subjugate themselves to a particular form of governance.
If you need any sort of confirmation check the Poll referring to this very thread in relation to the numbers partaking to those who've read & are aware of this issue. Now take that limited cross section of a voting public & then spread it UK wide ! Pretty much sums up the apathy & diffidence of the population.
To summarise, what needs to change is not necessarily the style of voting, but more the lack of voting participation. Personally I'd make it compulsory, yes there'd be resentment & folk'd probably turn that resentment into protest & spoilt votes, but at least it'd be 100% turnout, so there'd be no come backs, it'd be a case of you had the choice, no one to blame or hide behind.