Initially, Victorian recruits enlisted for life and would be entitled to a army pension after 21 years service. There were also disability pensions paid determined by a medical board at RHC. In 1847 short service army engagements were introduced - 10 years with the option of extending service to 21 years. By 1870s this was replaced by 6/6 and later 6/3 - 3 = on reserve. Most soldiers serving in AZW were on short service engagements. What this meant was their service documents were not retained - so only in the WO97 series held at TNA were service papers of those entitled to a full army pension or those had been granted an early medical pension were retained. Most of those docs related to short service men were destroyed by the War Office. The only way to compile the service of these men is to consult the medal roll, pay and muster rolls and casualty returns and of course, if survived, the discharged document issued to the soldier himself. Fortunately, in the later 1880s the War Office decided to keep all WO97 documents. Nevertheless, we can also work out that H Berry 25B/407 was issued his number in Aug 1874 and H Berry 25B/837 in Jan 1876. 25B/407 served with the Mounted Infantry and was with Lord Chelmsford on 22 Jan 1879 and possibly joined 80th F after the campaign. And 25B/837 was with D or G company at Helpmekaar. Each Company Colour Sgt (also known in those days as the 'Pay Sgt') would carry a pocket sized roll book in the field - none of these rolls have survived after the entries were transferred to main Battalion Roll held by the Battalion Paymaster. There are no quick answers I am afraid only hard graft.