Hi
I would suggest that you need to take this up with both the Local (District?) Council (the Planning Authority) and also the Local Highway Authority (who will have agreed the changes to the Highway) to facilitatae the new estate access arrangement.
The LHA is likely to have an Engineering/Roads Team, who will have technically audited the new junction and then supervised its implementation to standards.
The LHA will also have a Road Safety (or equivalent) Team who will have the records of requests for speeding enforcement etc. If the location is known for speeds above the posted limit then if nothing else the LHA should have asked for a VAS (vehicle activated sign) reminding of the speed-limit.
The two Authorities will be as indicated but the Departments/Teams may be called different.
L-K