Radicchio, so pretty, so revolting

It really is beautiful. It made me ache with longing while it was growing. Fantasies of radicchio with walnuts and goat cheese might have occupied an unreasonable proportion of my early winter thoughts.

Radicchio 'Treviso Precoce Mesola' (seed from Thompson & Morgan, UK)

I wish I could wax lyrical about how good it finally tasted. But no. Just bitter. Overwhelmingly bitter. I even tried forcing under pots for months. These experiments included trials of whole heads and sprouting shoots grown entirely in the dark after being cut back to the root. The leaves emerged just like they should have when deprived of any light: pallid, laced with pretty light pink. But still entirely inedible. And I have an unusually high bitter preference. Even my sophisticated friends, inured to some seriously out-there leafy combinations, rejected the tiniest shred incorporated in a salad.

Sometimes heritage salad greens don't work out so well.

Maybe it needs frost, something we don't have here? Ideas?