Indeed my friend, as I have one that you certainly don't have, and with providence to boot. For I have Eddie Barber's and Norman May's original prototype HW35 Vixen .177 built around a pre-safety Hoffman variant (the importers that pre-date Hull Cartridge) from May 1977.
For those who don't know, Eddie Barber was the man responsible for launching Airgun World magazine as well as being the other half of the picture regarding The Vixen's development with Norman. After the Vixen, Eddie moved on to develop the AIRGUNAID SP-5 .20 Hunter in conjunction with Don Grey: Eddie was -- and will always be remembered as -- a true Airgunning Legend. RIP Mr Barber.