If you got caught doing 94mph mate, your speedo would have been reading around 100mph so you should have known you were takin the piss a bit. An excuse of not knowing your speed when at 100mph on your speedo is pointless. Theres quite a bit of engine noise difference to start with.
Now i got caught like you at 97.7mph, this was on the A19 and my speeding fine was an SP60. I was fined £60 and recieved 3 points.
Now as to insurance, i have my own evidence that you dont need to tell them until renewal, UNLESS IT SPECIFICALLY SAYS IN YOUR T&C.
I was caught last April doing 97.7mph and never told my insurance company. The worst thing happened and i crashed my car, badly!! I crashed my car in September, writing it off!! I went through the claims department, they asked for my license and sent it back with a cheque for £12000. The 3 points did not need to be declared until renewal. I am with Tescos car insurance.
Even if your policy does require you to tell them of a conviction during your years cover and you dont and then you crash your car, they will still pay out. Minus what extra that your speeding fine would have upped your premium by. So £100 or so!!
Now my missuss sister works with Norwich union insurance and she has told me what ive said above, and with my own evidence from Tescos on top of that, it goes to back it up even more.
To make matters worse, i had modded my car quite a bit, upping power by 30bhp, changed alloys/lights/window tints etc and never declared a thing. We already get ripped by the insurance companys. They never said a thing and still gave me a cheque for £12000.
Ive never heard any stories of insurance companies not paying out because they havent declared something. All that happens is the price that you would have been charged comes off your settlement figure.
Its your decision mate!!