Possible Clues:

• Shut up a little quintet
• Five from hospital department housed in accommodation
• Write a little for small group
• Half a decade to write a short thank you note?
• The fingers of a hand, e.g
• Set of five things
• Basketball squad, e.g
• Shut up and take notice — this group's bigger than ABBA
• Writer contacts politician over a party with five members, for example
• Ten roughly accommodated in apartment? Only five here