Paul,
The term Multiple-Earthed Neutral system of supply, may help you.
The Neutral is terminated at the 'Star-Point'
of the Star side of the Delta-Star(11kV/400V),Berm Transformer, the Neutral is also earthed at various points along the lines, out of the secondary side of the X-former, just depends upon the length of Radial run, normally we like to earth the Neutral at every point possible, but this is also done at every consumers installation via the N-E Busbars.