List of courtesy titles in the peerages of Britain and Ireland

Columns: Peer | Son | Grandson | Great-grandson
The Duke of Montrose | Marquess of Graham* | Earl of Kincardine | Viscount Dundaff | The Duke of Roxburghe | Marquess of Bowmont and Cessford | Earl of Kelso | Viscount Broxmouth | The Duke of Manchester | Viscount Mandeville | Lord Kimbolton | The Duke of Northumberland | Earl Percy* | Lord Lovaine | The Duke of Leinster | Marquess of Kildare | Earl of Offaly | Viscount Leinster | The Duke of Wellington | Marquess of Douro | Earl of Mornington * | Viscount Wellesley*

Example questions:
What is the seat of the peer in the peerages of Britain and Ireland whose son holds the oldest extant title in English peerage ? | Who is the grandfather of the man with the title in the peerages of Britain and Ireland created in 1664 ? | Who created the title in the peerages of Britain and Ireland of the peer whose grandson is Viscount Ipswich ? | Who was the first person to hold the title in the peerages of Britain and Ireland of the peer whose great grandson is Viscount Dundaff ? | How many times has the title in the peerages of Britain and Ireland of the peer whose grandson is Lord Howland been created ?

Answers:
Arundel Castle | Duke of Devonshire | Charles II | David Lindsay | Six