There’s a 1988 Olwell boxwood flute, model baroque - 4 piece, with one key, up on e-bay just now:
http://cgi.ebay.co.uk/Baroque-one-key-flute-boxwood-Patrick-Olwell-/260603947758?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3cad34aaee
Item number: 260603947758
I play one of these in rosewood (kingwood, I think). Patrick made one batch of these, which he said are virtual duplicates of a Rottenburgh*, and one batch of A440 of his own design, probably loosely based on a later flute or flutes. I would say that the Olwell Rottenburgh is one of my favorite flutes, right up there with the Cameron Grenser. I am amazed that Patrick made, early in his career, some world-class traversi (Mine had been played by a professional player for the better part of 20 years), but dropped the idea completely and quickly.
*The ebay lister says a GA Rottenburgh, but I think it’s his father, IH. It has a scale length an inch longer than my Noy GA Rottenburgh (and my other rococo flutes), which would indicate a narrower bore, and that it’s probably based on an earlier instrument.