I'm feeling a bit left out so here goes. Mine does this too. [:D] Only comes on when driven hard though. (Which is quite often.) I will change the sender as a matter of course at next oil change with a better quality oil.
You should'n't overfill with oil because this can cause crankcase pressure which could cause oil to exit through unusual orifices normally breather pipes. Could also creat air bubbles in the oil which is not too good for lubricating. More often than not though it just burns it in the combustion chamber. Not good if you have a cat. (converter that is, not the animal.)
I wouldn't have thought a little over is enough to worry about its just being over cautious. IMHO that is.
The dealer also sells BP 10w40 oil for £12 a tin. Works out cheaper than Halfords.
Depending on the condition of you engine you may want to put in a 20w50. I use Duckhams Q in my 220 and have always been happy with it.
wow... for sure I do not miss that kind of pricing[:(!][:(!][:(!]
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