Hi
would be interested to see how you get on, i noticed my button on the other day. Turned it off and noticed a day or so later it was back on. I turned it off and then re engaged sports mode at around 50 mph and felt no difference i.e drop a gear etc? forgive me for mentioning this but i used to have an Astra (company car not choice) and when the sport button was pressed in this it clearly dropped a gear and revved like crazy, is also sounded like a bag of nails.
Lee