Complex sentence: While looking for new batting talent, Allen often promoted young amateur batsmen; of these, several emerged in this period, including Peter May and Colin Cowdrey, who had successful careers and were part of a strong English batting line-up.
Split into simpler sentences: While looking for new batting talent, Allen often promoted young amateur batsmen, of whom several were emerging in this period. Several of these, including Peter May and Colin Cowdrey, had successful careers and were part of a strong English batting line-up.