A bit off track, but interesting.
Their famous tins were boldly embossed in the metal "Huntley and Palmer Reading"
As soon as war was inevitable every tin had "Reading" squashed flat - for some reason they thought it a security risk to "reveal" that H&P were at Reading!
The tins never did reveal their contents - whether biscuits or not!
So at least some secrecy was preserved
esdel