I'm another one who watched this film on UK television as part of a '60s season tying in with the release of Tarantino's ONCE UPON A TIME... IN HOLLYWOOD. Tarantino champions it, but I'm afraid I don't see what the fuss is about. This is a typical kind of Bond rip-off, mired in '60s excess and some very silly and dated moments. The mannequin-smashing opening sequence is so overbearing that you almost feel like turning off, and if you persevere you end up in a typical story about a secret agent versus a criminal mastermind. The film does have some solid action sequences to recommend it, but they're outweighed by endless sexy dance scenes and Judy Geeson being annoyingly girlish (why this was amusing in the '60s I have no idea). Vince Edwards made his mark in Kubrick's THE KILLING but he seems ill at ease here, although Peter Vaughan is good value as the villain of the piece.
Review of Hammerhead
