When the fake telephone repairman plants a bomb under the table in Simon Templar's apartment, the bomb is held in place by 6 suction cups. A bit later, when Inspector Fernack examines it, the bomb has only 2 suction cups.
For most of the show, Jenny wears her hair down. But while recuperating in The Saint's bed, her hair is up. Given that she is recovering from a bullet in the shoulder, which would make lifting her arm very painful if not impossible, it's hard to imagine how she managed to put her hair up.
Just after Simon Templar makes his initial appearance on TV in place of the dead reporter, he and Hoppy return to their apartment. There is a very good close up shot as he turns on the light. It is obvious no one on this production had ever been to America and seen a US style light switch, its a very British design.
Though this was taking place in New York, the television set in Grandel's apartment was a Decca and the one in Simon Templar's was a Bush "Deluxe Twenty Three". Both are British sets and would not work in the US.