Thank you, I've made progress due to your replies, badapple and Nowherebrain. Looking at the command help for pstring gave an example of an array of strings, which I've used to create the array successfully (I think).

Code:
TEXT tScreenGreen =
{
string ("screen_knowyourenemy.bmp", "screen_nointruders.bmp");
}


And then through a lot more trial and error, figured out that I needed to use this to access it:
Code:
(tScreenGreen.pstring)[0]


So thanks everyone! I'm back on track.