hook up a mini digital voltmeter tapped to the battery. it will give you piece of mind and let you know if there's a charging problem. Not sure of the sealed units but a wet battery on a 2-phase 900SS should read as follows:
ignition off: 12.6V (fully charged) idle to 1500 RPM: about between 12.6-13.4V above 5000 RPM about 13.6-14.2V (above that and there's overcharging)
These number may be slightly different on a dry type battery.
for a 3-phase, it maxes out at about 13.6V at 5000 RPM.
Is the weather so bad in the UK in the winter that you can't ride all year round?
Hear in New York City we certainly get snow and salt on the roads but I can get a least 1 ride per month in during December-March (with electrics of course).
Apart from the fact I cant really afford to ride during winter Edward - you have hit the nail on the head - it does not get anywhere near as cold as you must get there but the English government DUMP thousands of TONNES of salt and grit on our roads at the slightest sign of frost, nevermind ice!!!
My days of exposing bikes to stuff like that are long over I think.