This is something of a grey area in this instance, because it is illegal to excavate the highway including the footway without permission and to access a driveway without a dropped kerb. However, as you already have a dropped kerb it could be argued that the property already has dropped kerb access. We would suggest contacting your local authority - you may find that paying for an extension of the current dropped kerb is preferable to negotiating with the council over the use of kerb ramps.