Sebastopol is definitely has the most fencing experience in this field. If you have a cursory glance over his lifetime form figures, you’ll probably come to the conclusion that he just doesn’t like winning!
In all fairness, he almost always runs a solid race, though he does have a tendency to lie down and give in towards the business end of the race.
If he can make use of his experience, he may have a chance – but last time out you’d have thought it was his chase debut (jumped awfully), so he’ll need to bounce back.