Broadback,

your method sounds good but I am not sure I fully understand it.

I use plastic electric wire conduit and blue water piping. Cut 2 lengths
of conduit to suit, insert into a length of piping to suit, push the
free end of each pipe into the edge of the bed

So two small lengths of conduit are pushed into a longer length of water
piping and the free ends of the piping pushed into the soil? What does the
conduit do inside the (middle?) of the water pipe?
Why conduit and water piping? why not make the hoops of just conduit?

You now have hoops across your bed
over which can be laid the netting.

Just lay the netting loose over the hoops? Any need to attach it?

If you have a fine net it will even
keep the cabbage butterflies off. A cost effective and long lasting
solution I find, especially if you lash out for good quality netting,
not the plastic stuff.

Not sure I have seen netting which is not plastic; what is it made of or
what should I be looking for?

thanks, Davy