Help doing some research

[Craterloads]

Brother in law found out today his granddad was in the UK in 1939 as part of the Kings Indian Orderly officers and just trying to find some more reading for him.

Found a couple of snipets for him

http://king-emperor.com/Photographs - King's Indian Orderly Officers 1939.html

https://trove.nla.gov.au/newspaper/article/51592635

Subedar-Major Sardar Khan, Sardar Bahadur, OBI 1st Class, 2/8 Punjab Regiment;

Subadar-Major Sardar Khan, Sardar Bahadur, has served 32 years with the 2nd Battalion, 8th Punjab Regiment, a unit raised in 1799 at Marsulipatam as part of the Madras Native Infantry. He served throughout the War in Egypt, and was in the Waziristan campaigns of 1921-24, and North-West Frontier 1930, 1936-37. Sardar Khan holds the 1st Class of the Order of British India. With it he received the title of Sardar Bahadur, "The Brave Warrior", and additional pay and pension.

Theres this thing on the national archives, not sure if related, but cant seem to access it

https://discovery.nationalarchives.gov.uk/details/r/6eb94d00-b1d2-401c-8478-d2e1c2682d82

Reference: IOR/L/MIL/5/713-715

Might be something in that but dont have the foggiest where to begin, any help would be appreciated.