Right, fair play to VW customer services, as they promised me last week they would call be back over my query, and sure enough today they did.
What they are telling me is that the GTD will not have it's own brochure, but instead will be incorporated into the standard MK7 Golf brochure, with just the GTi being kept separate. He tells me this information came direct from VW marketing, and will coincide with the relaunch of the MK7 brochure in late May / early June to coincide with the MY14 updates.
Also, as a side issue, they have now 100% confirmed, that the Dynaudio not only comes with a Sub in the boot, but that it fits into the space saver spare wheel (as per the new Audi A3), and therefore you still get a spare not a silly can of puncture foam that ruins your tyre. Happy days !!!