We found getting permission for the EoG mooring at the house we brought to be the least stressful part of the whole purchase....however Im not sure if it's harder if it's just say a field without a property or postal address etc...and whilst there was a small boat previously moored here we had to complete a new application and pay the fee etc which to be fair was all processed very quickly as getting the permission was a condition of us buying the property. You can apply for the permission before you purchase the land.