Well that was easy - just got a tight grip on the knot and twisted it from side to side and the whole thing crumbled and pulled out of the handle, whatever was used to secure the bristle just crumbled to dust.
The plastic / Bakelite handle socket is 23.5mm diameter by 40mm deep, so obviously I'm going to have to clean the residue of the old adhesive from the socket using a Dremel and then partially fill the socket with resin to provide a platform for the new knot to sit on, allow that to set and then fix the new knot into the handle with epoxy resin
Steve
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