I am thinking of building a lean-to greenhouse in my back yard, to grow
vines and tomatoes and the like in, to double as a kind of
"conservatory-lite". Rather than buying one, I was thinking of making it
with poles and plastic sheeting, and filling it with large pots, but no
benches or shelves.

Can you get poles which lock together in any combination to make a "bespoke"
greenhouse, at all? I was also thinking of using semi-opaque plastic
sheeting too, rather than glass or plastic windows, to give the light but
not necessarily the view. I don't mind having a view, but it's not that
great through plastic sheeting anyway, and I am overlooked by the back of
the next street full of terraced houses, so it's not that amazing a view in
any case. Would having it semi-opaque reduce the amount of light getting in
to any significant degree?

Any top tips would be well received!

Andrew