I had been researching an individual who had been awarded an OBE in 1918, to find out more information you'll have to write (by old fashioned letter rather than email), to:
The Central Chancery of the Orders of Knighthood,
St. James' Palace,
London SW1.
They were very helpful and were able to track down the individual in question and provide info on their awards.
If you give all the details you possibly can on the individual (addresses, date of birth, roughly when the award(s) were made), they should be able to help. However, as far as I remember they won't be able to give any details as to the reasoning behind the award. I think there might be a broad reason, for instance "services to charity", but they don't have any biographical details relating to the award (at least not for the early ones, I couldn't say regarding more modern awards). Hope this is of some help!
I can't quite remember where in my mess of papers the reply was, but I don't think there was too much more information than available in the Gazette. I was looking up a political figure and hoping for further information on the people who nominated him, and there definitely wasn't anything of that nature available for records at that stage anyway.