[DrBob]

The speedo cable can be removed from the top or the bottom, by unscrewing the outer cable from the back of the speedo and from the drive gear. If your cable is broken you will probably have to remove both ends to remove the broken pieces.
Make sure you remove the old cable before you buy a new one, as a broken cable is only one of the things that can cause the speedo to quite working, and you don;t want to buy something you don;t need.

As for the battery, roll the rear wheel up on a brick or block of 2x4. Remove the two bolts from the back of the bottom of the battery box, and the bottom will swing open to remove the battery.