I noted on Sunday last that my Rover's ammeter was wavering slightly about the null position whereas normally it is perfectly still. The voltmeter will normally read between 13.5 and 13.8 volts (0.5 volts less than the voltage across the battery) was reading 14 volts. The ignition warning light was behaving erroneously, either staying illuminated once the engine was running, then gradually fading out as the engine revs increased, or behaving normally to a point but then illuminating simultaneously with the headlights being switched on. In both scenarios, the ammeter showed no discharge, and the voltmeter remained on 14 volts or even higher. From my experience this behaviour is not symptomatic of brushes, nor is it typical of problems with the bridge rectifier. Instead to me they suggest the regulator is at fault. My plan is to replace the latter tomorrow, then following a test run I will report back with the findings. The existing and the replacement regulators are branded Cargo, which is a product originally manufactured by the Danish company Holger Christiansen. In 2008 the company was acquired by the Bosch Group, with the Cargo regulators now manufactured in China. My Rover still runs the original factory fitted alternator, albeit with different brushes, slip ring, bearings, and regulator. It has seen a total of over 407,000 miles (655,270km) of service running with regulators branded as Lucas, Ingram, and Cargo. Of these, the Cargo products have been clearly the most reliable.