Thanks Lynn,
I obviously have a lot to learn about pickaxes. I raised the dimension question as a friend of mine bought a few dozen and I am trying to help him sort them out. Obviously there are many detail differences because these are forged.
Bert found they are dimensionally different, apparently because the type used on vehicles was larger than the type carried by Infantry.
Most are marked with the British Broad Arrow, a date and manufacturer name. Bert thinks the helves may be US ones.
If anyone can point out the differences between US, British, Canadian, Australian and other? ones, we can add this the collective font of knowledge here on MLU Forum.