On the 306 (V reg 1.4 Meridian) the "STOP" instrument panel warning light has been coming on intermittently. It looks like the fix was to clean some contacts. I started with the temperature sensor contacts (as suggested in this NG) but I think the actual fault was a connector near the aircon reservoir (at least that's what it is according to the vague descriptions in the haynes). This seemed to be corroded (and is within splashing distance of the screenwash filler). A bit of servisol and wokring the connector in and out seemd to fix it.
Chris