OK...when you remove the "facia closing panel" from under the steering column, you will have access to the SRS plug... disconnect it and check there is no corrosion on the pins, then push the two parts together so it's a snug fit. If the wiring harness clip to attach it to the cross-member is missing, then secure it in place with a cable tie.
The Cruise Control might not be operating for several reasons..
Don't forget you need to activate the CC with the switch to the left of the hazard warning switch before the steering wheel buttons work...
also the CC ECU is known to fail with age. While you have the "facia closing panel" removed, check that the CC ECU is properly seated...it's an oblong- shaped box, rather like a large relay just to the right of the steering column.
EDIT: Do you have a copy of RAVE (The Rover "Active Viewing Environment" ) it's 1300+ pages of workshop and electrical troubleshooting manual in a searchable pdf format and is indispensable.... You can either download it by searching on the web, or better still buy the CD for a few $ from "Dave's Interesting Things" on this forum -see homepage (supports the forum)

