Thanks for all your replies regarding the nearside window not dropping and the interior light not working when you open the nearside door. I have gone through the reset procedure but it did not work. I think HOPWOOD may have hit the nail on the head with his faulty switch idea. Seems too much of a coincidence that the same switch could operate the window drop system and the interior light. Had a quick look under the door trim today just in case a wire had become loose but all seemed well. A job I fear for the garage to sort out or maybe a trip to the factory. Oh for plastic sliding windows.
As for the cruise control, this I have now mastered, just dont ask me how.