Munty - I have tried to do the canes as you said but being a girly 8 stone weakling I can't get the canes in deep enough - the soil is clay on the lottie( but it has just been rotovated again) I have even tried making the holes by hammering a shorter cane in and it still doesn't work - any suggestions?
Rather than canes, which can bend and even snap when trying to force into clay sub-soil, I prefer to use round steel rods. 8mm diameter will do for shorter supports, 10mm will do for longer and 12mm is resilient stuff altogether. I have some luxurious 16mm dia' ones, sawn at 8 foot each.
Being careful, you can usually force/twist the ends into most ground and can apply a hammer carefully to the tops in a way that you cannot with bamboo cane. Have the top ends bent right over and back on themselves for safety - only a couple of inches so they look like a mini shepherd's crook. Closely hammered and this forms a useful top loop as well for string and such. The ultimate is to have tiny 'arms' (say 2" of 6mm round bar) welded every foot or so (pointing up@ 45 degrees) along the above-soil length, for tying to and stopping string slippage down the rod. There's no need to paint them in my view. They'll last years and when rusted look ok in any case - Rustic in fact.
Just plain black mild steel bar will do. Any local wrought-iron gate and fence manufacturer will have loads of it. All the sizes I quoted above comes in 6 metre nominal lengths, usually a bit more for cut-off bad end allowance and such. In other words (in old money) more or less 20 foot lengths. So you can get 3 x 6' 6" lengths (in fact 2 metres - doh) out of a full bar, or 4 x 5' lengths or even 5 x 4' lengths. Or 2 x 8 footers and a 4 footer. Just ask the supplier to cut a length equally into however you want it - you're not fussy enough to an inch or so. Have him bash the ends over - it's 30 seconds each with a vice and an anvil. And a decent hammer of course. Current prices should be about 5 or 6 quid per 6m bar for 12mm round, say 4 quid for 10mm and 2 or 3 quid for 8mm.
If they set the saw blade at 45 degrees too when cutting the base ends, you get a fairly sharp point (in fact a deadly one) to enter the ground even easier.