Fish, Chips and Rachmaninoff
Aside of the high-tech crime world there is a team who smuggle and distribute diamonds. At sea an archaic fisherman and his naive deckhand net the chips, shove them down a fish's gullet and head to their secluded cove.
A slinky sixties attired girl swoops into the cove in an Austin Healey and scoops up the prized catch, makes a detour for her personal benefit, and delivers the chips to the team leader.
He and his accomplices reside in a stately home, and another of their number, being an accomplished pianist, gives recitals while the leader distributes the loot to selected guests.
Their friend a curative hypnotist sort of brainwashes the members, and each time an electrical storm strikes one falls down dead.
Then there is this inspector who is on to their game, and after a few wild goose chases is ready to pounce. By the time he does, the team is reduced to a frightened few.