I've been wondering for a long time who made John Steed's bowler, but now I found this picture:
From the liner, it's an HJ. HJ still sells a black and a light grey bowler: http://swaineadeney.co.uk//perl2/v2.cgi?page=/catalogue/details.html&productid=416§iontoken=herbert-johnson-hats
From the liner, it's an HJ. HJ still sells a black and a light grey bowler: http://swaineadeney.co.uk//perl2/v2.cgi?page=/catalogue/details.html&productid=416§iontoken=herbert-johnson-hats