Thanks for your input again mate, I appreciate all of it. 

It is very unlikely that my labels come off as I tape all the label with sticky tape, and so far I don't believe this has ever happened to me. Certainly I would find it hard to believe that of the 6 'missing' parcels more than 1 could have been due to a label issue. I also only ship within Australia so thankfully I avoid a lot of issues others have selling Internationally.