Just as a pointer here, always ALWAYS go not guilty.
We went to court, me and a mate, he was on cam being chased by a volvo t5 at 128, me i was slower at 121. We both went to court pleading mitigating circumstances as to why we were speeding, but disputed the speed. They just threw it out without us even having to enter the court room, too much time to argue when they have hundreds more to prosecute.
Incidently, i got a letter from CPS telling me in this instance it was deemed necessary to be using such excessive speed.
We said we were on our way to help a mate who was a taxi driver being attacked.