Spotted - you would be more than welcome!
The postcreting is really, really easy. You dig a hole. You put the post in roughly level (to the eye). You sploosh in a fair bit of water. You add enough powdery postcrete mix to fill the water. You grab a level and you just make sure that the post is level on top and at 90 degree angles all round. You hold it there for a couple of minutes while checking Mumsnet gardening on your phone. It sets in about 5 minutes. Bingo. It honestly could not be any easier. I was dreading it a bit, because I did proper mortaring in the garden of brick paths etc and it's a real drag - you have to keep mixing up the cement and it dries so you're against the clock and it's hard, physical work. This is a doddle by comparison! (My kind of DIY!!)
Alternative - I am utterly shocked at your neighbour raiding your plot. How rude!
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Rooster Brassica netting: after pigeons tore my cabbages to shreds (do not worry, fair readers, they did recover) I developed a cunning plan. I bought a roll of blue alkathene pipe from Screwfix and a roll of scaffolding netting off the internet.
I hacksawed the pipe into fairly long pieces, so that the arches are tall enough to house caulis and cabbages without problem (the pieces naturally form an arch because the pipe has been kept in a circle). I push four of these arches into the ground per bed. I then cover with the scaffolding mesh, weighing it down with stones (or plastic bottles filled with water). It is easy, quick, involves no skill whatsoever, and it works. I was worried that the netting would be too dark and shade the brassicas too much, but they actually seem to like it. And the scaffolding mesh also keeps out some insects too. My brassicas have been pristine ever since.
Cedar - I love the sound of your blue squash!