Possible Clues:

• Use tax cut by empty Exchequer
• Work out Queen's contribution to tax?
• Work for schoolboy, perhaps, in trouble
• Keep-fit
• Work out problem in textbook?
• Beneficial activity that ends the answers to starred clues
• Put in practice a duty involving Her Majesty
• Pianist's scales, e.g
• Training that every prisoner should have
• Work out duty bearing on being brought up