Well, beard you are not alone. I spent a lot of time on the weekend trying to figure out some of the spirals. What snake/s are you having trouble with?
There is this Video , but I haven't seen it, and it only advertises basic single and double drills. I think there are other video's around.
Charly's comment about the local juggling group is a good one, as is glass's offer. I was in a juggling shop in Melbourne on the weekend, and the sales guy, a juggler, said that someone did snakes at their juggle jam.
Other suggestions: Get a copy, and decipher Schatz's book. It has lots of good diagrams and info on snakes. Better still, get a copy of Anna Semlyen's book on modern club swinging.
As you are in the UK why not attend one of Anna Semlyen's Cosmos Jugglers Workshops. You can also look in the library at Anna's site for info on basic Snakes
Finally, I will try to help if you have a specific problem, but I think I'm in the same leaky boat. Good Luck