The strip was heralded a week earlier, in The Dandy No.1201 (dated November 28th 1964) with a small ad (shown above). DC Thomson's art staff could always design a good ad and this was a great teaser for the series. Brassneck was to replace Joe White and the Seven Dwarfs which had concluded that week.
A week later, in The Dandy No.1202 (dated Dec. 5th 1964, on sale Nov.30th) Brassneck's adventures began! For the first few episodes, Brassneck had three pages, which then reduced to its standard length of two pages. The artist was the excellent Bill Holroyd, who was perfectly suited to this type of comedy adventure story.
Here's that very first episode, with Chuckler Charley Brand (they soon dropped the 'Chuckler') meeting his new metal pal all those years ago. Click on each page to see it larger.