Possible Clues:

• You might get into this for 24 down covering up one of those doing a few strokes
• Something you might get into on the Lido, for instance, covering up one of those doing a few strokes perhaps
• A clue to some cut for tight-fitting garment?
• Witnessed on the Lido, for instance, covering up one of those doing a few strokes perhaps
• Train we miss commuting; in summer, it might get packed?
• Some cut, it is suggested, to make skimpy garment
• Item of beachwear