Sorry for the surfeit of alreadys! Actually, I'm undecided about whether the proposed new speed limit is a good thing or not - would like to see some accident stats perhaps. But I suspect the reality is that people in modern cars will ignore a speed limit that's too low and the police don't have the will or the man/woman power to enforce it.
My brother was a traffic cop for years, he never stopped anyone on the motorway unless they were going over 90mph as there was so many drivers doing that .
So if the limit goes up to 80 looks like your OK to do ninety.