thanks guys
just hit a snag, dmaleny, you're correct
took screw off desktop to slide panel and there's a seal
if the seal is broken, my warranty at Harvey Norman is invalidated, not sure if it's next May or the following year when warranty runs out
i'll have to give them a ring tomorrow and ask if it's OK to have a look - otherwise i'll leave it be or ask them if they can check while i wait at store
