Hi Dave
nice to here about another Austin in restoration proces.
you are looking for these Austin publication:
Driver´s Handbook Lorry 3-Ton, 4x4 Austin K5 GS and K5 GS Airportable K5 A.T.Portee K5 Recorder A/A Mark 1., publication No. 2222A
Maintenance Manual and Instruction Book for Lorry, 3-Ton 4x4 Anti-Tank Portee and General Service, publication No. 2048
PM me your chassis number and I can find for you contract number. After then we can find for you corect publication.
I have for sale procejt Austin K5 if you are interested.
Could you share with us pictures of your K5?
regards Radek