I duly acquired 'A very funny business' by Leo Baxendale
The DC Thomson fun book
and this issue of the Sunday Times magazine
Dated July 29th 1973 it shows (on the front cover) W. Harold Thomson and inside (over 5 pages) it recounts some of the history of the firm, but mainly the secrecy that surrounded DCT at the time and their antipathetic attitude towards the press - "...we never give any information about anything to anybody" is a quote from their spokesman.
As the magazine is harder to track down than the books I will share scans of the magazine (which I have just acquired). The magazine is lightly larger than A4 so the scans have had to be 'doubled up' for each page, so apologies for that.