Scruton claims that Tristan's Honoris a variation of Hero.  This is only possible if one compares the G, B-flat, and A-flat of this motive to the G-sharp, B, and A of Hero.

Motive Labels
“Tristan” – (Windsperger, p. 41)
“Tristan the Hero” – (Lavignac, p. 294)
“Tristan’s Honor” – (Redlich, p. 23)
“Tristanpreis” or “Tristan’s Prize” – (Pfohl, p. 218)
“Tristan Appears Before Isolde” – (Fischer, p. 9)
“Tristan’s Tragic Defiance” – (Kobbé, p. 118)
“Sitte und Heldenehre” or “Custom and Hero’s Honor” – (Pfohl, p. 217)
“Destiny” – (Kufferath)
“Morold” – (Cleather)
“Vengeance of Morold” - (Hight, p. 278)

Tristan's Honor – Order of occurrence by Act and Scene
Act I: Scene 5