Hi Luukyy
Thank you for your reply, having read that I now understand the problem. I have been making a few mistakes whilst exporting the model. If I explain it may help other noobs.
At first, I tried to export the model after "grouping" the individual objects together. When I used the model (in a C# programme), it was fragmented (i.e.the individual objects occupied random spacial relationships to each other). By "merging" the objects and then exporting, the model looked fine but I had the problem you pointed out where the model would only use one texture. I then realised that I was not setting the export operation up correctly.
After pressing file>export> and got the export dialogue window, the "Frames" option was not ticked. Once this was done ("frames only for groups") the "grouped" (but
not merged) model exported fine with the textures associated with each object on the model.
Hope that was clear. I'm still in the early stages of learning to use AC3D but thanks to your help I'm making progress. I assume that the way I've gone about the export procedure is Ok in terms of not putting a performance penalty on the application - any guidance is again greatly appreciated.
Thanks again Luukyy