I guess SS (try saying that fast without spraying!) van would be a closer term than GTS, as a HQ Sandman van had the same grille and seat treatment as SS. But according to Leo Pruneau the outcome of Bagshaw's round table meeting with vanners was they wanted "GTS from the seats forward and nothing done from there backwards" (so they could add murals and customise the rear). So I guess the beancounter's interpretation of that was what HQ Sandman ended up as. I guess Leo forgot all that when he came back from overseas in time to finish off the LX SS and did the HX Sandman as they made the HX stripes mandatory on Sandman (which many vanners of the day hated as they had to get them off, so much so with HZ they added a delete stripe option) and deleted the GTS guards so the Sandman logo sticker worked with the stripes.