I hate to say this, but I think that you are misrepresenting the source that you have linked to.
The YouGov poll is only indicating that forty-eight percent of those who voted for the Liberal Democrats may be less inclined to vote for them again, which hardly supports your claim that 'Liberal voters are ready to defect'.
If you take a look at the article in detail, rather than just looking at the headline, it's worth noting that the poll was financed by Ed Millaband's Labour leadership campaign, that the sample size was only 2500, and that the likelihood of voting was divided into two categories with only twenty-two percent being much less likely to vote for the Liberal Democrats.
This raises serious questions about the poll in terms of bias, not only because of the sample size, but also because of the funding source. Polls which are funded by parties are, after all, always meant to generate findings which are favourable to the party which provided the money for them. Indeed, one of the first rules of analysing any poll conducted in the discipline of political science is to look at who funded it.
Having dealt with that issue, do you have any evidence to back up your statement about Liberal Democrat policy on tuition fees?
On the issue of VAT, I wasn't thrilled by the policy decision, but your broad brush approach to this issue does not really give much insight. The Liberal Democrats are constrained by the coalition agreement, and also while some of them may say that they agree with it, this does not mean that they do in private, but to vote against it could bring the coalition down. Is this worth the risk? Can we be sure that Labour would not raise VAT in exactly the same way as the Conservatives would have done? I cannot recall Labour ruling out a VAT increase during the election campaign.
Finally, what do you mean by a true left wing party? Labour is nothing of the sort, so I think that you need to clarify your point here.
