Stanpit speed management

I attended a meeting last week with Dorset highways to see the results of the latest speed data collection exercise which operated in October outside The Ship in Distress.
Mean speeds measured in both directions hovered around 23/24 mph and the all important 85% speed at about 26/27 mph. I am told that these figures support the 30mph limit which runs along Stanpit but would not sustain a 20mph limit which I was hoping for. So whilst we have shown a considerable decrease in speeds as a result of our intervention, I am struggling to find a way to insist on the lower limit being applied.
Out of interest I asked about speed data collected from Bure Lane at the same time and was told that this was considerably higher running at an 85% of 34/36 mph. Now that was the level that we were operating at in 2007 at Stanpit before we conducted our survey and took the action we did. Clearly Bure Lane will now be of more interest to the Police camera team as a far greater number of vehicles are being driven at speeds above the limit than Stanpit.
As you are aware DCC has now taken control of all highway matters so CBC will have far less influence over these matters.Frustrating though this is, we do have some redress by using our County Councillors to take the message to DCC highways. This also applies to the Purewell Cross debate and the school crossing at Mudeford Lane. I was however successful in again bringing to the attention of the engineer the problem of flooding outside the toilets at Purewell and was assured that the matter will be dealt with.