Possible Clues:

• Fast-food freebie, sometimes
• 'If the start of 18 across is sick, this is his replacement (6)'
• Sends off those not feeling well? Tell the barman to pull the other one!
• Subsequent prescription order
• Second cup of coffee, e.g
• Replenish the stock of
• Sends off only those not playing well? Tell the barman to pull the other one!
• Seconds from the soda fountain
• Pen insert
• One in middle of fight, sick for another round