Related Clues:

• Renters of more strict sort
• Behind about to turn less flexible
• More strict
• More serious author writing for schoolchildren, for example
• More backward? Well more inflexible anyway
• Back with little hesitation the more rigorous
• Novelist right to be more rigorous
• More demanding manoeuvre catching navy
• Rear gunner's final two are more serious
• Not as lenient
• Not so lenient
• More grimly serious
• More flinty
• Back Queen, being of greater severity
• More dour