Possible Clues:

• Redoubt (anag) — become noticeable in an unwelcome way
• Ring and baronet lacking refinement become painfully obvious
• Old boy, impolite, taking time to butt in
• Push out old boy over time getting ill-mannered
• Redoubt rebuilt to be more prominent
• Butt in middle of ashtray held by old boy with no manners
• He died, supported by Duke in real push forward
• Be offensively prominent