There is lots of information to be found in Army Service records - both genealogical and physiological. Service records can tell you date/place of birth, next of kin, height, colour of eyes/hair/complexion etc. They can differ in detail however. The records will of course also give you their military history as well. The problem is, unless you know their service number or, at least the regiment they served in, it can be a slow process. Looking at his age, he would have joined up within the last 3 or 4 years so you can narrow down his enlistment dates somewhat. I don't know what regiments were based at these barracks - I know the Royal Artillery and Army Service Corp were located in the Hampshire/Andover area. I also think there was a Naval Barracks in this area as well. I will see if I can find out more about Alverstoke.