Can anyone help? At the very bottom of the frame under the bottom bracket (where you used to get your postcode stamped by the local bobby) there is a bit of plastic that helps guide the two gear cables. In trying to get a gear cable out, I ended up breaking it. Anyone know what it is called as I imagine I will only be able to source a replacement from a specialist Specialized website?
You're looking for a "bottom bracket cable guide" - you may not need a Specialized one, though.
Take a look at the pictures online, the generic Shimano is probably fine.