Possible Clues:

• Artificial body part
• False part of expert’s research paper
• Dodgy hip, so rests getting replacement part?
• Sister hops about on artificial leg, say
• No end to writing a dissertation? This may supply missing part
• Former pupil meeting magnificent in Douglas
• Tom's paper providing artificial substitute
• Replacement part
• Artificial bit in writing (not English) at start of dissertation
• Expert's dissertation in support of Long John Silver, say?