New government can easily reverse or change the policies of previous governments, the civil service jut enacts what the government of the day tells them to do.
Sort of. The civil service has lots of people with their own agenda which they push to the elected politicians when they ask the civil service for options on how to solve problems
The civil service doesn't push their own agenda. They are tasked with finding solutions to enact policy decisions, they provide the best solutions that they can that will fulfill the policy presented by the government. A civil servant cannot push their own agenda and the civil service as a whole doesn't have an agenda except to serve the government of the day to the best of their ability regardless of their personal politics.