Originally Posted by MadRod

It wont, you will be charged with exceeding the 70mph limit so 71 is enough. If all procedures were followed you will be held to have done 143.
The fact that your car cant do that speed now is no proof in law that it was not capable of it at the time. Dean charged with doing 169 in an Escort with a book Topspeed of 144, they even said he was travelling South on the M1 when he was going North. He was still charged & banned.