there was a previous post on here about use of the argos shelfing units for a cage/run- i bought a few in the sale but find the plastic bits that are supposed to join them are not secure enough and if you build any reasonable size- it can fall over easily- has anyone else used them? if so- how did you secure it together? i dont want to waste it all- but can't use it with the plastic bits suplied. any ideas?