This medal is heavily overpriced. 1/24th Isandlwana casualty medals are selling for between 6500 - 7500 GBP.
For what its worth, I would advise you to keep an eye on the market place, as these medals DO come up fairly often.
Another strategy is to make contact with a few high level dealers and adivse them of your serious interest, as they will likely be able to source a medal for a more realistic price. This is how I obtained my 24th Regt. Isandlwana casualty medals.
In answer to your question, yes this is about as much information as you should expect to find on this man. The only other avenue of research available is to have the muster rolls searched for the time he was in the British army.