[Lynn Eades]

Ford did a similar thing in the 70s. With a Kent designed engine and German gearbox design in Escorts and Cortinas, meant a mix of both standards, and hybrid bolts.
Identifying from a bolt head has become far more difficult in the last 20 or so years with many new manufacturers.
The Australasian standard doesn't help.
Now that I think about it, even Ford of Canada made hybrid bolts and nuts for carriers with BSF threads and American (unified) standard heads.

Then there are the tool sets intended to cover all possibilities (eg 19/32", 25/32", and 29/32") made to fit British standard heads, as an extension of an American standard tool set.