Untaxed vehicles regularly being parked in school car park

We are experiencing regular authorised parking of untaxed vehicles, some also without valid MOTs being parked in Heritage House School car park spaces. We have been reporting these on Fix My Street as abandoned vehicles as sometimes a vehicle can be left for weeks or even months. Up until recently they were being dealt with and, if necessary, removed. In recent months whenever we report a vehicle we get an email back almost immediately to say 'No Further Action'. I have queried this with the BC Facilities Team through our portal but not received a response. Please can you advise what, if anything is being done about this nuisance parking? The school car park is BC land and is causing huge problems for staff as they are often unable to park.