Complex sentence: On both occasions he came fourth after the major parties (there were 19 candidates at Newbury) and encouraged by these results, the AFL changed its name in September that year to the United Kingdom Independence Party (UKIP).
Split into simpler sentences: On both occasions he came fourth after the major parties (there were 19 candidates at Newbury). Encouraged by these results the AFL changed its name that September to the United Kingdom Independence Party (UKIP).