I too am worried about an in/out referendum. It's very easy to present a caricature of the case against the E.U. and much more difficult to present the case for without getting into the kind of detail which makes you sound boring and/or hectoring.
It's the usual pattern with extreme parties, pretend there are easy solutions to complex issues. UKIP and the SNP have a lot in common, both telling people they can leave the political institution they are part of without any negative consequences.