OK, probably the first of many, here goes...
Series 2a 2¼ petrol. There is a yellow warning light in the speedo labelled "cold start". It's off when the engine is cold, but comes on when the engine gets fully warm. I've checked the wiring diagram, and the earth for the lamp goes through a switch (1), then through another switch (2) to earth. I'm guessing now*, but switch (1) must be on the choke cable (continuity when choke is pulled out) and switch (2) is a temp sensor on the engine (continuity when the engine is warm). The result being that it warns you if the engine is warmed up and the choke is still out. However, switch (1) on the choke is faulty (i.e. permanently on), giving the symptoms above. (I'm guessing because a quick check in the p*ssing rain revealed neither a switch on the choke cable nor a likely-looking sensor on the head.)
Am I there, or nearly there, or is it something else entirely?
*No owner's handbook, and Haynes is silent on the subject.