+30mph on a speed limit tends to mean a ban in most cases according to the law as it was when i was busy avoiding these sorts of things
what you want to know is how they caught you
is that the average speed? in which case you WILL have been going faster
or is this a fixed camera location
in which case you oculd have mitigating circumstances (bigger wheels have throw your speedo reading out, tailwind, down hill, etc)
if you cask for a picture you can see how much of a bother you are in, if it shows the car full up with people then you can say you wern't driving but can't say who was (you'd need to bring along several people who could have been in the car with you at the time) opr you can pull the old "i wasn't driving because i was drunk" (assuming it was later on and you'd had a few cold drinks)
there are ways around it but you need to start with a tale that you will stick to
no point in saying "but i wasn't going 104, was going 99.8" and then try and say someone else was driving

then again, the judge might just decide to shaft you and there is nothing you can do about it