Information and image from Robert Chilton.
The company supplied destination blinds.
Their blinds tended to have a much wider variety of sizes, thicknesses and even styles, with some of the letters looking quite different between the different names. Some short names are quite bold and some long names have smaller letters rather than simply narrower letters.
The example shown is thought to be printed by Kelbus and is from a Cricklewood allocated DMU, and example differences are in the horizontal part of the A being at different heights in Harpenden, St. Pancras and Moorgate.
The other main destination blind suppliers were E.W. Matthews and T. Norbury & Co.