It looks like some sort of artisan work.
A single picture and in that size is not good enougth to appreciate the quality of the work.
If you can take more pictures. Showing the detailed work, that would help to apreciate the set.
Try to take a really close up of the Knigth, becouse it is usually the pice with more handy work, and usually is what determine the value of a set.
If you know what material it is made of, that helps too, if it is wook, what brand of tree. Also if it have marks, like signature or something... Also the condition of the set affects the price, if it have chips or cracks, that makes it loses value.
Besides quality of work, condition, and materials. Antiguity is the next criteria to determine the value of a set. For instance did your Dad purchased new? did he remember how he gets it? where?
The next criteria is the rarenest of the set, if it was mass produced, or it is a only one time deal.
The last main criteria to determine the value of a set is if it have some sort of historical significance. For example, if a previews owner was someone famous, or important. Or if it is feature in some media, like a movie, or a magazine.
Hope this helps you out.
My Dad is wanting to sell his chess set - pictured in avatar - but for the life of me I can not find anything similar to compare it against. Any help would be greatly appreciated.