Ball joint
Elise ball joint are not a specific item. The same have been used on Vauxhall (Opel) Kadett. Parts number are: Quiton Hazel: QSJ883S, Deplhi: TC163.
To remove it, you'll need two tools: A specific Ball joint extractor (Eliseparts) and a Scisor extractor.
See DIY section for further details.