Tim. What a brilliant idea! Yes please, do bring a couple of snakes with you when you come.
If that doesn't do the trick, then I don't know what will.
I don't think it matters about the colour or markings. I think I have read somewhere that it is the shape the birds and other animals respond to. In fact, bring more as they might work on the rats too.
My resident snake seems to have moved away. I haven't seen him for a while. Mind you, I am not surprised, he probably got fed up with me saying "Hello, my 'andsome" every time I saw him.
, on Flickr