SJW
Get in touch with Barry by PM, or maybe Keith. I believe in the thread Kieth was commenting how he had seen a robust porter recipe by one Barry Cransto, and Barry replied that he remembered them leaving off the n on the end of his name. It is quite possible he doesnt wish to part with it, though, and if that is the case, he could probably put you in the ballpark of a great place to start your own experimentation. I thought that he had put up the recipe before, sorry to have mislead you.
All the best
Trent