So I have decided to go back to the original method I was using, based on tutorial 5, after finding a line of code to help filter out the tracks that aren't relevant to that page - "TrackProductID=$this->ID".
However because you can't check the checkbox which is how a TrackProductID gets assigned until after you have created a new entry they are lost. I therefore need to find a way to either add in an 'OR is NULL' argument to the above line or automatically check the checkbox so that the TrackProductID is assigned by default. And then remove the checkbox so that it can't be accidentally unchecked and lost. Does that make sense?