I now have a little more information; the alternator is rated at 38A. which of course has to run the injection, ignition and management systems, the lights, charge the battery back up after starting the engine and so on before trying to warm anything up.
As Martyn points bike alternators are different from car type alternators...maybe not internally in how they work but mainly in the sheer physical size that they can be.
When I get some more real info I will pass it on.
At the moment my feeling is that gloves and socks or insoles are no big issue, bigger items like jackets might be pushing it a bit if you've got the lights on and the heat on at full blast. I'm not convinced about heated seats - I think they might be eating up the safety margins.
Passengers just need to grin and bear it!
