The Heirs of King Kong or "Gli eredi di King Kong" as they say in Italy is actually the film Destroy All Monsters, rebranded with a cheeky little reference to the greatest of the apes who of course isn't in the actual film.
Yes, those are indeed a couple of different images of Shado astronauts from the British TV series; UFO, who, unsurprisingly, also don't feature in this film. - Sneaky!
This one is for you, Tim. It seems you weren't the only one who thought the actual suits used in this film were uninspiring.