Sorry to ask this question, but I've read other threads on the subject and I'm none the wiser.

I have an 08 1.9CDTi 120 Excusiv with CD30 and basic 2 line screen, if possible I would like to upgrade to CD30 with trip computer screen. What I gather from other threads is that it's basicaly a case of either getting a CD30 with screen or buying a screen that has been *divorced* from it's original head.

1) Will a new (secondhand) head and screen go straight in and work without any faffing about?
2) Will a divorced screen work with my existing CD30 or will I need to take it to a Vauhall Dealer to get it programed?
3) I saw mention of a washer bottle level sensor, do I need this, I'm only really interested in the trip computer part?
4) What is *divorced*?