cpt the vickers posts are likely to be S0001014 and 1012 they are down towards the north Norfolk railway - unless there are others lurking in the rhododendrons in the Park
That they are, leftorium. These are all VMG emplacement variants. Listed on the Norfolk HER as type 20A for a standard VMG emplacement and Type 20/2 for the conjoined double emplacements. They give no source for the type numbers so after some discussion on the PSG forum it was decided to type them as VMG emplacments until a drawing turns up, a nice research project for someone in Norfolk perhaps ;-)