Answering my own post (for the benefit of future searches!), having now managed after much head-scratching to remove the lifting part of the keel……………
The liftable keel pivots on a large stainless steel pin that traverses the fixed keel and passes through the top forward corner of the lifting keel. The pin has a diameter change such that it can only be driven out from the starboard side and lies behind wooden plugs driven into the fixed keel at either side. The lifting keel has a 4mm wire attached to its top rear corner which passes up through the sampson post and over a pully at the mast base onto the coach roof. The keel itself has two polymer discs bolted to each side to minimise movement in the slot. It is very heavy – needing two or three to carry.
To remove the lifting keel loosen the lifting cable, drill out the wooden plugs then knock out the steel pin from the starboard side. The keel then needs to be manoeuvred to stern so that the polymer discs align with the wider central section of the keel slot and allow the keel to be moved downward and out.
The membership association for owners of Dufour Yachts