How signs work in my part of England is that, come an election, out in the countryside you get farmers or landowners putting up lots of signs along the roads, which looks quite impressive - till you realise that all those signs along a stretch of road just mean that maybe one farmer (and maybe his or her family)has decided to vote that way, or want peopole to think they have.

I don't know how far you can read much into signs. Whether people put a sign up for one party or another is as much as to do with if they want to annoy or soothe a neighbour as anything. Our MP's dad lives in a house across the road, and at the election the most unexpected neighbours stuck up posters for his son, because he's a nice old bloke. Whether they all voted for him, God knows.