Il grande attacco (1978) credited, as Colonel Jürgens. Geoffrey only has one scene in this all-star cast WW2 movie, playing a sleazy SS colonel who tries to blackmail Samantha Eggar into sleeping with him. He yet again dubs himself for the English dub.
Io tigro, tu tigri, egli tigra (1978) - third segment, as Swiss general. Yet another role as a German-speaking character, and he again dubs himself for the Italian dub even though he only appears in one short scene.
Sam & Sally (TV series) - season 1, episode 6: "Bedelia" (1979). I haven't been able to find this episode, but according to the listing in Radiocorriere TV, he plays the role of Kellerman and is credited as Geoffrey Copplestone.
Aragosta a colazione (1979) credited, as Mr. Duchamp. Geoffrey has a pretty good role here, featuring prominently in the lenghty party sequence, and yet again uses his own voice in the Italian dub. An English dub also exits, but I haven't found it so I don't know if he dubs himself there too...
Dottor Jekyll e gentile signora (1979) credited as Geoffrey Coppleston, as Archibald Gold, P.A.N.T.A.C. manager. He appears in a few scenes here and dubs himself for the English-language version, but not the Italian one.
Return of the Saint (TV series) - episode 22: "Dragonseed" (1979) credited, as Nightclub manager. This British TV series received some co-funding from RAI, and so some of the episodes (including this one) were shot in Italy with Italian actors as guest stars. Geoffrey only appears briefly in one scene.