I first came across this plant at the Wentworth Castle Garden in South Yorkshire, now reopened under the shared partnership of Barnsley Council, with Northern College and the National Trust.
There are over 63 acres of garden and a huge area of surrounding parkland to explore. The restored Victorian conservatory is well worth a special visit on its own.
I don't know the common name for this plant or even if there is one? But as cabbages go this is pretty spectacular.
I have found it is easy to grow from seed, and the plants have survived two winters in Poynton. The only problems with it are that it is loved by slugs, snails and caterpillars, and it really needs to be strongly staked.