Interesting, one interesting thing to note is that Arbutus is adapted only to coastal Mediterranean climates. Llandudno has a self-seeding population. There are specimens in Chester and a few in a garden near me, but the Chester one, and the ones near me cannot set fruit. I suspect this is because the climate is not warm enough in the winter. Like Olive trees in their natural habitat, they flower in winter, so frosts tend to destroy the flowers. However Llandudno doesn't have the level of frost we have, and certainly not the level of frosts that Chester has, therefore Llandudno's climate seems very suitable for the Arbutus.
Given how fussy Arbutus unedo is, and given it's propensity to self seed just within its natural range, I would classify it as a native plant that needs to be conserved on the great Orme. As long as they're left alone they''ll grow into a woody thicket which is develop a similarity to Laurisilva forests of Portugal and Canary Islands (Indeed Arbutus unedo, Prunus lusitanica, and Ilex aquifolium (our common holly), are native laurel forest plants of Canary Islands and Portugal
They are generally quite big trees when sheltered, the one in Chester is a good example, I'd say it grows to the same height as Prunus lusitanica - thats larger than a fully grown Holly Tree (Ilex aquifolium) anyhow. I'd say the open nature of things keeps them dwarfed.
Thanks for the ID, Brassica oleracea. Well we don't have these in Wirral, surprisingly, I think they must prefer alkaline soils, rather than our acid soil.