The second existing episode and in fact the final one of all is A Sinister Sort of Service which is right out of The Avengers casebook. A supposed security organisation is masterminding crimes using a computer. The spree is causing government concerns and seems to be carried out by a gang wearing goggles for no apparent reason unless they go for a communal swim afterwards.
While all these elements may seem hokey to modern eyes, it was made in 1967 and many of the ideas have been recycled in various films and tv series since including the idea of inviting the hero into your lair to tell him your plan and then not guarding him properly. There are some good points too; notably Simms getting in on the action and scenes celebrating Adamant’s 100th birthday. A good one to finish on.