@will Hi Will, thanks so much for your reply. I'll admit as a newcomer, I'm dimly aware of what an object is, but wouldn't know where to start in fixing/adding the correct code (whilst working on this project, I am trying to read up to educate myself, in parallel with a 'cut and paste' approach on other peoples' code that works. Any good tutorial suggestions on C programming that are beginner orientated would be appreciated).