The first gig was on 18 May 1978, the second on Thursday March 13 1980 (flyer below). Both were recorded and can be heard on the box set TG24 (cover from cassette release of 1978 gig above).
Incidentally, prior to Throbbing Gristle band members Geneis P.Orridge and Cosi Fanni Tutti were in the performance art group COUM Transmissions. They staged their pieces 'Birth of Liquid Desires' (1974) and 'After Cease to Exist' (1976) at Goldsmiths, the latter in the same year that they were denounced by an MP as ‘wreckers of civilization’ following their famous ‘Prostitution’ exhibition at the Institute of Contemporary Arts.
Later, P.Orridge and others founded Thee Temple Ov Psychick Youth (TOPY). In 1991, Fred Carter of TOPY had a performance called ‘Shock, Information and the Negation of Control’ stopped short by the Student Union at Goldsmiths. It involved self-mutilation, with Carter cutting himself to a soundtrack of drones, industrial rhythms and hymns.