Complex sentence: However Clough also regularly submitted transfer requests and had a tense relationship with some of his fellow players, and was especially irked by Boro's leaky defence, which conceded goals as regularly as he scored them.
Split into simpler sentences: However Clough also regularly submitted transfer requests and had a tense relationship with some of his fellow players. He was especially irked by Boro's leaky defence, which conceded goals as regularly as he scored them.