Rolf v De Guerin: http://www.bailii.org/ew/cases/EWCA/Civ/2011/78.html. A small building dispute in which the client’s offer to mediate and the builder’s unreasonable refusal was crucial to the costs order.
Vale of Glamorgan v Roberts: http://www.bailii.org/ew/cases/EWHC/Ch/2008/2911.html. A small boundary dispute where the losing side might not have been ordered to pay costs if he had specifically asked for mediation, rather than making several settlement offers.