I've also grown picklers in nine-inch pots quite successfully this year.
These are De Barletta but any bulb onion sown from seed seems to work.
The food hedge experiment is coming along nicely with the runner beans in tubs flowering as they twine their way through the privet. Many of the flowers are white and don't show very well but they are there!
If this works as well as I hope it will I'll be on the look out for more climbing vegetables for next year to fill the fifty foot or so of hedge that's available.