Hi Matt,
Is there is enough pipe to push the split part into the car, or into the boot?
If so, a small piece of brake pipe will allow you to join it back up. If the split is right in the middle, get some thin rubber hose, (even Halfords will sell it), and put a small piece in with 2 pieces of brake pipe.
If you nip into any tyre place, I am sure they will give you a little piece of brake pipe foc. We are only talking maximum of 2 pieces at 1" long<S>.
Quick fix & saves taking the whole back end apart & will be as good as new.
Cheers, Shane