There isn't a digital version of it (officially), it was only ever designed for print and therefore does not display very well (for technical design reasons I am not qualified to explain) on digital screens.
It needed to be digitised, and therefore redrawn so it could be digitised without looking odd.
It also had a significant number of symbols etc. added for the modern era.
(Turns out, according to the article below, there was a digital version of RA that had been made for producing lineside signage)
A detailed discussion of the redesign:
https://thebeautyoftransport.com/20...ayfinding-signage-and-rail-alphabet-2-part-2/
The Wayfinding Design Guidance, which shows all of the graphic elements:
https://www.networkrail.co.uk/wp-co...NR_GN_CIV_300_01_Wayfinding-Design-Module.pdf (I'd suggest this is the equivalent of the BR Design Manual)
Here's a rather nice sign using RA2:
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