The Adventurer is one of the least remembered of the ITC filmed series, and likely little seen or heard of since the mid-1970's. Along with The Protectors, it marks the start of the wind-down of the golden era of the genre. Both series may have benefited from being in an hour-long format like their predecessors, to develop the characters and plots and dispense with the quick editing. I believe they were made half-hour long due to the requirements of the US network.
Gene Barry seems rather tired throughout, and a bit old and overweight for the role, but he does bring a likable presence to the programme as the smart lead, set against the straight-laced & impeccably-mannered Barry Morse as the ministry man. In some respects they compare to Tony Curtis/Roger Moore in The Persuaders (1971) but there is less camaraderie & chemistry between them, and Morse is more like the authoritative judge (Laurence Naismith) character in that programme, rather than the adventurous Lord played by Moore.
The Adventurer has a larger regular support cast than usual for ITC, including Catherine Schell and Garrick Hagen, and they are more energetic than Morse and Barry. Progressions from previous ITC series include much of the incidental music and the extensive location footage (including much in industrial Europe). In tandem with traditional ITC stiff upper-lip these point to the concurrent Van Der Valk and later series like The New Avengers and The Professionals.
By 1973 though, seventies realism was replacing sixties optimism and substance was superseding style. Gene Barry at over 50 years old often looked incongruous in contemporary fashions.
His character, along with the Simon Templar and Jason King-types was on the way out, we already had Van Der Valk and were waiting for the imminent arrival of The Sweeney and The Professionals. Thus The Adventurer, though more entertaining than might be expected, fell rather unsatisfactorily between earlier and later genres perhaps explaining why it languishes in relative obscurity.
