Complex sentence: In response MacNeice initially "began to go out a great deal and discovered Birmingham", but with his mentor E. R. Dodds leaving the city in 1936 he felt increasingly isolated and accepted a lectureship at Bedford College, London.
Split into simpler sentences: In response MacNeice began to go out a great deal and discovered Birmingham. With his mentor E. R. Dodds leaving the city, however, he came to feel increasingly isolated and in 1936 accepted a lectureship at Bedford College, London.