Happened to me a few years ago, lorry pushed me off the road, claimed he did not see me, to be fair i was in an slk, so once he was pushing me along and off the road, he probably could not see or feel me, but he was quite a way behind and had to cut the car up that was behind before he hit me, spun me off the road and he just carried on. Fortunatly the car behind me followed him and got the reg and as it turns out his broken number plate was on the road and wedged in the back of my car.
The police insisted on prosecuting him, but he lied to them and had to own up when they waved his number plate at him, but then started blaming me, very very long story. It took over a year before it went to court, but they sucessfully banned him from driving, this was the polices choice.
I was with direct line at the time and i ended up doing a lot of the work myself on the insurance front and have to say i got a good lawyer.
The police will take their time as in the scheme of things it is not a serious crime, but have to say they took it very seriously and they where the ones that pushed it through and wanted to prosecute.
I had a hair line fracture in my collar bone and he did about £3000 worth of damage to my car, so it was not a case of not following it up. I was fortunate in a way as the lorry was owned by a very big crisp company, so tracking the vehicle, driver and their insurance co was easy.
I left Direct line after this, as the amount of work i had to do was a joke and i paid out a lot of my own pocket and had to wait nearly a year because of all the denials from the driver etc and DLs inability to not lose files and follow things up.
Personally if it was not a lot of money i probably would not bother, but people that drive off regardless of how minor really should not be allowed to get away with it.
Good luck hope you get it sorted.