Clue: Alcoholic drink prohibited, for a start, in a company car (4,6)
Answer: PINA COLADA
Explanation: Alcoholic drink prohibited, for a start, in a company car (4,6)
**P**[rohibited) [for a start] + **IN A Co.** ("company") **LADA** ("car") 
*Pina colada is Mrs Loonapick's favourite cocktail, a mixture of rum, coconut milk and pineapple juice, served shaken with ice.