Dennis
I have done a bit of reading on the process used at the time of the ABW to appoint officers to the IY and it is quite different to that of the regular army. A lot of info about the IY process may be found in Will Bennet's "Absent Minded Beggars" ISBN 0 85052 685 X. You might profit from getting a copy of that book.
As I understand, commissions for junior officers in the initial IY were "made locally" (by the Lord Lt of the County?) and had to be approved by the Imperial Yeomanry Committee. The War Office banned Regular Army officers from joining the IY. Any application forms would have been kept by the IYC, I have to assume.
The New Yeomanry (2nd Contingent)was raised by Army Order with a Deputy Adjudant General appointed to recruit it. Applicants for commissions had to be recommended by someone who could give a valid opinion of the applicant's abilities. Applicants were supposed to be interviewed by the officers raising the contingent; it appears many were not and references were unchecked before appointments were made. Again, I assume applications would have been kept by the DAG.
Commissions in the 3rd IY Contingent again seemed to have been at the discretion of the DAG - with more care taken in selection.
Thus trying to look for applications for Commissioning documentation in the IY seems to be a hopeless case. I can only assume that - in the parlance of a later conflict - IY commission holders were "temporary gentlemen" and the relevant papers discarded. Some time ago, djb did a look for me in the Brit. NA for IY commission applications and he couldn't find much at all.
The book Mike recommended (Boer War Services of Officers etc) is often quite handy for activities of officers actually in the field. However, background of an IY officer might be more likely found in Army Lists and an entry might give geographical clues.
Dennis, not much to help you here. It seems you have a research job in front of you. Good luck with your project. Should any member of the forum be able to correct any misapprehensions I might have over the "officering" of the IY, I would be happy to hear same and learn from them.
Regards to all
IL.