Yes, I had one of these leaflets too. It appears that this time they prefer to hide behind the Royal Mail rather than come round and face people with their crap.
A few years ago one of them did come round here, though, and very quietly put a leaflet through my letterbox. So quietly that I didn't hear it, and my letterbox was an old fashioned one that clanged loudly. So he/she was very careful not to be detected. When I found it I felt like they'd sneaked into my house and it made me feel uncomfortable and angry. So I rang their answerphone to complain and asked them not to delivery anything to me again. To be fair, my language was a little strong and I did say that I'd rip up any future leaflets and stuff them down the neck of the deliverer, but I know that I didn't swear because both dses were with me.
A month or so later I had the police on my doorstep. They'd recieved a complaint that I'd left a threatening and abusive message on the BNP's answerphone. The BNP had submitted a transcript that more or less followed the gist of what I'd said but they dropped in a raft of F words, made up a whole section and beefed up the threat to something altogether more sinister.
I refuted the whole thing and told the police what had really happened, especially that I'd felt violated by the sneaky leaflet tactics. They were great, very sympathetic and said that I wasn't the first person that this had happened to - BNP's Telford office were quite well known for making rubbish claims against people who stood up to them. The officer said he'd be taking no further action and told me that I could, if I wished, think about pursuing them for slander. Tempting as it was I had no way of proving the actual content of the conversation and was too knackered with work and small children to go ahead.
I'm just looking forward to the day when the b*stards come electioneering round here for real.