Complex sentence: From the 1960s onwards the town declined as a holiday destination, Southend revived it's fortunes as the home of the Access credit card, due to it having one of the UK's first electronic telephone exchanges.
Split into simpler sentences: From the 1960s onwards the town declined as a holiday destination. Southend regained some popularity as the home of the Access credit card, due to it having one of the UK's first electronic telephone exchanges.