By Mark Jefferies It’s late at night and Ibiza’s streets are heaving with clubbers but Zara McDermott is in no mood to party. The Love Islander feels surrounded by crime. With just four police officers on duty at Playa D’en Bossa, the Spanish island’s party heartland, the crowd of around 30,000 holidaymakers seems more sinister than social. Zara, 27, has come to the island she once partied on to make a documentary about its darker side, as wealthy partygoers have attracted drug dealers and organised crime gangs. Shadowing Guardia Civil officers for Ibiza: Secrets of the Party Island, she soon …