Boundary of car parking area

Thames water have recently tried to install a water meter to our propertybut were unable to do this as they cannot access our outside stopcock which is located at the boundary of a small car park and our garden wall and which is now overgrown with shrubbery and hedges which the council do not currently cut although they cut either side of the car park. I would like to request that they cut this area back so we are able to locate the stop tap for purposes of installing a meter and should we need to turn our water off in an emergency in the future? Thank you