From their website, the following little snipppet from their most recent newsletter is instructive:
The cork – screwcap option has proven a great success and we will continue to allow you to make the choice. It seems that for mail order customers preference is evenly divided and in the trade the screw cap is a higher proportion than the cork option. I make no excuse for my preference for cork, but I am also realistic and happy to continue offering you the choice. Maybe in the future the cork companies will finally get it right!!
Fascinating! We can safely assume from the prices charged that theirs is a reasonably well-informed clientele. It might also be interesting to see how the preferences change over time. I imagine there will be a pretty solid core of customers who refuse to countenance anything other than cork, but I wonder how big that group is? A couple of other makers who did part-bottlings in the past - Grosset with his flagship Gaia red blend for instance, dropped the cork option pretty quickly when it proved rather harder to sell. (Giaconda would have very little wine unsold whatever their closure, however, unlike Grosset.)
We'll have nearly as much fun looking back at all of this in twenty years' time...