I agree with you Shrinking Violet, the Nicandra (shoo-fly) plant is incredible. They suddenly appeared in our garden 2 years ago. We also live in Norfolk, but we were so impressed with this jurasic looking plant, that we took some down to our parents in Berkshire. If all Norfolk people keep doing this, there may be a pandemic. Ours grew last year to about 5'. They do self seed everywhere and take some getting rid of, but we use them to hide the compost bins and have a patch of garden to themselves. They are well worth having, if you keep them controlled. There's nothing else like them. Thought you might like to see some photo's.
You can see the size of them compared to the pansies underneath.
This is the beautiful flower
These are the chinese lantern shape seed pods they produce, which are just as beautiful as the flowers. The purple/black stems are also very striking. I get thousands of seeds from one plant, so don't let the plant seed itself. Apart from picking out the thousands of plants you don't want, your neighbours may not talk to you again.