Never heard of it, but see that M&S stock them. If they taste thate good, I might fork out to try one. They're supposed to be 'heirloom' does that also mean OP? Sounds nice though, looking forward to seed swap if you grow them successfully. Don't I remember you saying you don't grow big ones or dark ones?

Gardening is an excuse not to do housework
Greetings from Salisbury
Qualified member of the Confused Nutter's Club