All of those videos are out of production, but are still available at online sellers.
British Dictionary definitions for sellers
Peter. 1925–80, English radio, stage, and film actor and comedian: noted for his gift of precise vocal mimicry, esp in The Goon Show (with Spike Milligan and Harry Secombe; BBC Radio, 1952–60). His films include I'm All Right, Jack (1959), The Millionairess (1961), The Pink Panther (1963), Dr Strangelove (1964), and Being There (1979)
a person who sells
an article to be sold: this item is always a good seller