Once upon a time, I did a paper about a man who served in the 14th Surrey Militia. I struggled to find more about this unit, but it is not something I am familiar researching, so someone else may be able to help. If you could direct me to a reputable source on the unit history in the Boer War. Anything would be helpful. Unit rolls, actions, commanders, diaries, etc.
I was looking through old papers and remembered my failure. I would like to remedy it now.
EDIT: I was looking more and realized there may be multiple units that had battalions that might have used such a designation. Getting me to rolls of any of them would allow me to search for his name.
EDIT #2: Evidently, my research prowess has increased. I believe that is the West Surrey Regiment, but I am not certain of the Battalion.
I teach seminars on the war, and I've done work both in SA and in London that has crossed these classes of records. Militia units were a bit odd, but by the SA War they were attached to specific units of the regular army and within their chain of command. See this guide from the PRO/National Archives for a bit more on the militias. You can find a lot of Army Lists via archive.org here; for 1900 specifically, here's the B&W PDF (83MB); if you need 1901, it's right here, 100MB.
The 14th Surrey, however, doesn't seem to exist as a designation--there's a 1st, a 2nd, and a 3rd, all regiments, later re-established at battalion size, but I don't see a 14th. The unit history doesn't indicate one was raised, either, or that any of the militias had an active title as "militia" after 1881. But that may just be a failure of granularity.
A lot of records from that era have been digitized by genealogical services, but you can find out a lot from Kew as well. What you'll have to do is verify the actual unit command and that the unit title/level was what you believed it to be; there was a 14th Corps under the Queen's East Surrey Regiment's 4th Bn. So it's possible it was under one of the regimental heads, but there's no indication of it in the army lists. If you have a name and feel OK with a PM, I can try to dig a bit. Usually I'm looking for engineers, but there's a lot in SA War rolls at Kew (and at the National Army Museum in the city) that you can get into without making the whole trip blind. [edit: It's sometimes hard to use the dates, just because replacement and reinforcement corps/personnel were not organized as well as one would hope, but usually Kew has the paperwork.]
[edit 2: I did a brief dig into the SA Journal of Military History, which is online freely through 2013, and don't see anything obvious about the Surrey units.]