OK - Sorted
If this is of any use to any other noobs:
I had the FREE edition installed before getting the CD ROM and had downloaded some free assets into it.
When the CD arrived I just installed it thinking it would upgrade everything to the paid version and just ask for a CD key. This was not the case...
It loaded a V1 version of FPSC - and the imported assets under the TGC tag were still all present - however the Model Packs were not. Why that is I will surely never know.
I solved the problem by unistalling everything - including the TheGameCreators root directory, did a Registry clean, loaded the CD, updated to the 1.16 version then intalled the Model Packs.
I did lose the assets I already had of course, but everything else is now working.
I suspect they may be some registry conflicts going on between the model packs and the Free - v - Paid version. Who knows? God works in mysterious ways it seems....