SJA,
Welcome to the Board. Plenty of Paradox fundi in Oz, notably Grahme Wright who wrote Shooting the British Double Rifle, and Marrakai posts here often. The second edition of Wright's book has a chapter on Paradox guns and their ilk, the Explora, the Colindian etc. etc. as made by various in the trade. I believe that Ross Seyfried here in the States is working on the small bore W-R, a 20 gauge Fauneta and someone has written about successfully putting together LT heads for a Fauneta (late edition of The Double Gun Journal??). Suggest you do a google search with the terms "Paradox" "shotgun" and/or "Explora" "Westley Richards" and see what comes up.
Regards, Tim