"Me,nj, I was told fine would almost certainly have been increased."
You don't actually appeal as such, denton (though I appreciate that is the usually understood term). What happens is that you are usually offered a course (if the speed wasa up to Limit + 10% +9mph and provided you have not done one in the past three years) or a fixed penalty (up to 20mph over the limit in 20 or 30mph limits, up to 25mph over for other limits). You are entitled to no evidence at this stage (though they may provide photographs "to help identify the driver" provided you ask before naming the driver). You can decline these offers and opt for the matter to be dealt with in court. If you are convicted you face an income related fine (the lowest being half a week's net income, the highest 1.5 times that income), a surcharge of 10% of the fine (minimum £30) and costs which range from £85 if you plead guilty up to £620 if you go to trial (and possibly more if the prosecution has to call on expert testimony). So at the very best you will pay considerably more than £100 and you may (again depending on the speed) end up with up to six points or a short ban. So court is to be avoided unless you are sure you have a good defence, so you were given good advice.
Successfully defending a speeding charge on the basis of a disputed measurement is not easy. As I said earlier, the prosecution will produce evidence that detection was made by an approved device operated in the correct manner. The court is entitled to assume, in those circumstances, that the measurement is accurate. If the defendant doubts that the burden rests with him to show why (and simply saying "I don't think I was doing 95 so the machine must be faulty" won't cut the mustard). Many drivers believe that the police go out of their way to secure convictions and may resort to dodgy tactics to do so. They've no need to. It's like shooting fish in a barrel.