Even withdrawalist parties accept that electing any number of MEPs will not bring withdrawal one step closer, the EU doesn't work like that. One former colleague in UKIP, well intentioned but misguided in my view, claims that in 2005 UKIP's general election vote went up 50% on the vote in 2001 because of having MEPs. Maybe the number of votes did rise, but only because they had more candidates than in 2001. The actual percentage vote for UKIP was still only around 2%, similar to the percentage votes it was achieving pre-1999.
The problem is the public still don't care or know enough about the EU to be really bothered. Despite having MEPs since 1999 UKIP still haven't fulfilled their pledge of using MEPs to launch themselves into the UK parliament. Partly because they don't bother very seriously, partly because most people don't care about the EU, they vote on issues they regard as more important, and UKIP is still seen as irrelevant. The following quote from the Irish Times says it all really:
The European elections in Ireland, as in many other EU states, tend to be used as a mid-term review of the government by voters. The opposition also try to score political points against the Government rather than open an ideological debate about Europe or policy issues associated with the EU.
The full Irish Times article is here.
Let's face it the whole EU election is a sham. I have advocated abstention before but couldn't bring myself to do it when the ballot paper arrived. So I voted for a party that advocates withdrawal but I am certain will not get anybody elected. At least that way I know my vote hasn't helped directly put another snout in the trough.