So from what others are saying, the egg cup left in the galleries after several minutes after running the bike up to temp, is offset by the egg cup of expansion of the oil. When cold the egg cup that was in the galleries is now in the sump, and the egg cup due to heat expansion is no longer relevant. ergo, the level will be the same in both hot and cold scenarios.
With regards to my own personal experience, the light has come on, on only one of the ten journeys I have made since my original post, if the oil level was dangerously low as has been suggested, it was low for all ten journeys, but only lit the lamp once. In the interest of covering all the bases, I checked the oil as per the manual, and marked a line after seven minutes, and then checked it again after two hours, and there was no difference whatsoever in the level. I then warmed the bike up and topped up to the top line. On four journeys since, the light has come on twice.
Back to my original question, before I was accused of being an idiot, has anybody else had trouble with their oil light?
A new switch is £86, so I'll look for a S/H one, unless I can fix the old one.