July 2013.

I think this might be the last design change to my heavy framed Ecobed, at least for a while.

I have redesigned the pest exclusion frame and added a simple method for attaching the netting.

The legs of the frame now sit on top of the bed wall instead of being attached to the sides.  They have galvanised steel angle brackets to hold them in place, and use short pieces of galvanised steel builders strapping at the corners to increase stability.

Galvanised Tek screws (see photo) were screwed into the rails and base to provide hook points for holding the pest exclusion netting in place.  A piece of netting was cut to cover the north side of the bed, and another to cover the top and ends.  A piece of 75% shadecloth was cut to fit the South side of the frame.  12.5mm brass plated steel grommets were then fitted to the netting so that they drew it tight against the frame when slipped over the Tek screws.

This is what it looks like with just the south side fitted.

Here's the bed with all the netting in place.  I might have to find some weatherproof woven tape to stitch around the edges of each net to make the grommets more secure and stop the edges curling.  Maybe I will do that next time I make a set.
 
Features

1. The frame has been altered to provide a perimeter top rail.
2. It now sits on top of the wall flush with the outside of the bed.
3. Tek screws have been fitted to the frame to act as hooks so that the netting can be attached flush with the outside of the frame and the bed.
4. Brass plated steel eyelets are attached to the netting to slip over the Tek screw "hooks".

Benefits 

1.  I don't have to buy a huge piece of pest exclusion netting to cover the whole bed since the sides are separate pieces and the top and 2 ends are covered by a third piece.  This uses considerably less netting and can be cut out of much smaller pieces.
2. When not in use these nets can be rolled up and put into storage.
3. When heavier shading is required in summer, extra pieces can be made in 75% shadecloth.
4. I believe it will be a more effective barrier against pests than a loose fitting net held in place with pegs.  
5. It is a cheaper option then mounted timber framed nets, and requires little space for storing when not in use.