The third Folkestone Triennial is at its best when artists such as Richard Woods and Bob and Roberta Smith tailor striking works to the town’s geography

Antony Gormley sculptures lurk under the promenade, Richard Woods invades town with huts for second-homers, while Bob and Roberta Smith treats local kids to art lessons. An eye-catching battle is raging at the Kent seaside between rich and poor, social decay and civic pride