The message
from John Cartmell contains these words:

Q. Am I likely to be able to get such aluminium section and plastic fixings?
Where?

http://www.smithmetal.com/smc/asp/ma...=an&txthead=aa

or

http://tinyurl.com/epzal (eBay item)
http://tinyurl.com/m292l (eBay item)

Dunno about the fixings though. Perhaps you could hinge it and use
diagonal wires to hold it square - or even shock-cord diagonals so it'll
self-erect.

Will it be windy or indoors? I'd imagine it'd blow over quite easily outdoors.

--
Skipweasel
Pay no attention to the man behind the curtain.