Vanished tool makers: Dropstamco (Drop Stamping Company Ltd.) Birmingham, England

I recently acquired this set of "British Made" Dropstamco Whitworth wrenches.

1954

There's not a lot of information online about this tool maker. According to the "New Companies" section of the November 23, 1934 issue of The Colliery Guardian, the company was founded that year:

Drop Stamping Co., Ltd. — (Private company.) Birch-road, Witton, Birmingham. To take over the business of hot forgings manufacturers carried on by C., H., and A. Hickman, at Witton, Birmingham. Nominal capital, £3,000 in £1 shares. Permanent directors C. Hickman. H. Hickman (chairman), and A. Hickman. Qualification of directors, £500 shares.

It's not clear from the above whether Messrs. Hickman had a previous business under their own names, or bought another company and became its directors.  In any event, I can't find any information on C., H., and A. Hickman.  The "Dropstamco" trademark wasn't filed until 1949. Below, the factory in 1951:

Source:  Britain from Above

I can't find any information on what happened to the company.