Not really. They have no chance of power, so they say things which appeal, or might appeal to their target audience outside of those who'd vote for them for purely racist reasons. so they say things which might appeal to folk who are unaware of their extreme racist nature. Folk who might be alarmed by immigration or multi-cultural nature of our society, but aren't outright racist.
They're basically scooping for support from as wide an audience as they can get, and they use seemingly "fair" stuff to try and pull in that audience. They're not for actual fairness, obviously, or for actually treating people equally. That much is self evident, I'd have thought.
They're no more socialist or left wing than [insert name of right wing, but non-racist party of your choosing]. They're not about standing up for poor folk who are non-white, they cannot be socialist by definition, whatever they or others might say. Exactly, which is why they tap into the poorer, so called 'working class' areas, and which is why what 'success' they have enjoyed has been in such areas.
Your typical BNP voter, and fortunately there are not too many of them, would otherwise vote Labour. Whether that is true or not, I have no idea. But BNP voters are not socialists either way.