Yep the Wurth stuff is excellent, used to be able to get it free from my dads company as they have an account with them...
Dont use wd40 to clean your chain, its not a degreaser and will leave a protective film behind which will stop the lubricant from adhering properly.
I used to use a brush system which clipped over the bike chain which is really good, as helps keep your bike marginally cleaner during the process