Datatool Digital Gear Indicator. Breva 1100

Answers on a postcard… I have the chance of one of the above, which would be useful in stopping me initiating a speed wobble by trying to engage 7th gear at 69mph plus. Looking at Amazon, there is one review, which states that it doesn’t work on the 2007 Norge 1200. Ah. But that’s all it says. No explanation. Has anyone else used one of these? Any reasons why it wouldn’t work?