"J. Public" wrote in message On another note, I noticed a while ago that the P22 tube font has
square commas, full stops, apostrophes etc instead of the tilted square
'diamond' like ones. Does anyone know why this is?

nope - sorry!

The P22 Johnston font is a representation of the original Johnston
font for LT. That font *DID* have the punctuation as you've described.

Take a look at St. Pauls station, and above the platform exits you'll
see the square full stop.

Likewise any older line diagrams along the line will represent this as
well.