It grows well in a sunny spot - Devon. Has soft stems that have white liquid in when cut. We’d like to plant more of it.
This would be Euphorbia characias.
There are many, many species. Most of them have similar, to exact same care. This article will go over the care of Euphorbias:
https://www.gardeningknowhow.com/ornamental/cacti-succulents/euphorbia/growing-euphorbia-plants.htm