Asking this question in a DIY forum is like begging to be flamed, but here goes: I have a Wedgwood boar brush with a ceramic Wedgwood handle that matches my scuttle. When the knot needs to be replaced, I am hesitant to try it myself since 1) I am not particularly handy, 2) I live in a condo and don't have any kind of work area and 3) I am afraid of cracking or breaking the ceramic handle. So, are there any vendors who restore brushes that you all can recommend?
If you are ready to do it now, you could probably just ask if someone here would help. I'm doing my first one now, so I don't know that I'd volunteer, but I probably would after a few more tries.
I'm not trying to "flame" you, but you might find you could do it more easily than you think. Instead of a drill, you could simply dig it all out using pliers and some sharp implements (drill bits in the hand actually work fairly well for this). It would probably take you 45 minutes to an hour, with no power tools. With a ceramic handle, avoiding power tools might be a good idea anyway. Then you simply need some epoxy.