marquess, I'm looking at the most recent Debrett's.
The line of succession, after the new Marquess appears to be as follows:
1. Lord Anthony, b. 1961 (uncle of the new Marquess)
2. Arthur Alec. b. 2001 (his son)
3. Kenneth Edward David, b. 1975 (son of Lord David, 2nd son of the 5th Marquess)
4. William Henry, b. 1971(son of Lord James, 3rd son of the 5th Marquess)
5. Hugh Bertram, b. 1973 (brother of William and Alexander)
6. Alexander Blane, b. 1982 (brother of William and Hugh)
7. James Callum, b. 2014 (his son)
8. Henry Colum, b.1938 (son of Lord Robert, 2nd son of the 4th Marquess)
9. Alexander Colum, b. 1967 (his son)
10. Sullivan Joseph b. 1998 (son of Alexander, grandson of Henry)
Considering the new Marquess is only 32, and there are 4 in the top 10 under 40 (including 3 under 25), the Marquessate is in a lot better shape than a lot of other titles.
Brooke