The same happened to me years ago (1990) when I was caught doing 140mph in my Renault 5 GT Turbo.

I proved that it simply wasn't possible to do that speed in a '1400cc hatchback' ...... in standard form!!

What I didn't own up to was...... the big intercooler....hybrid turbo....groupA carb.....ported head etc etc lol!

I got off with a £40 fine because I had admitted to doing 'about 90mph'..... well I didnt want to completely take the piss now did I ??

Even had the jury come outside and take it in turns to sit in the passenger seat to see that the speedo was visible from it as to verify the statement of my passenger that I was doing only 90mph. Lol, what they didnt know that the guy in court as my "passenger witness" was a DIFFERENT guy to the one who was in my car when I was doing err.... 90mph, lol!!

I'd say fight it. What have you got to lose.

Our prisons are full of bum sex offenders anyway!