Will I lose my driving license for speeding tonight?

Even though I have only ped my test 6 months ago, I am a very good driver and have covered 20,000/30,000 miles within this time. I have never endangered any other road users and I am confident with my driving ability. That said, I like to drive fast when it is safe to do so. Tonight I was driving along a dual carriageway near where I live in the UK and there were very few cars on the road. I overtook one car and was travelling at 70mph, when I saw that the large vehicle which was pulled over at the side of the road was a van with its doors open, and I think I saw a camera stood stationary at the back of the van. I also noticed that the car in front of me was a police car. So I hit the brakes, and made sure that I pulled in behind him and went down to 45mph. The police car in front of me did not pull me over, but I think the police vans with the speed detection equipment automatically takes down the offender's details so there would be no need for him to pull me over. What are the chances that I will get a letter in the post? I was meant to be doing 45mph as a restricted driver but it was a 60/70 road and no one was on it. Will they be able to detect that I was a restricted driver even though it was very dark? On a side note, if real criminals had to pay an extra �1,500 each they would think twice before breaking the law. But instead all of their expenses are paid for (via taxes) and their freedom is not taken away as such as they are allowed all of the luxuries they would enjoy at home. From my experience, there are very few nice police officers and more often than not they have shirked their own responsibilities in the face of adversity... like the time 10 guys got jumped after a night out by some boxer and the police sat and watched us getting beat up... good job, good job -.-