If I go through the legal advice of the insurance would they be helpful?
If you check, I think you’ll find that they will not provide assistance to defend criminal allegations.
Could the “no sign” work in my favour?
Providing the offence was not in Wales and there was a system of street lighting in place, the only requirement for a “30” sign is the point where the limit begins. The streetlights provide the “reminders”. As above, post a GSV of the location.
The speed is too fast to expect a fixed penalty. The next you can expect is a “Single Justice Procedure Notice” informing you of court proceedings. If you plead guilty you can expect to pay a fine of a week’s net income, a surcharge of 40% of that fine and about £95 costs. The guidelines also suggest either a ban of up o 56 days, or six points.