Possible Clues:

• To a degree it's on to make the defence strong
• I stab on this for fortification
• 'There's a strong prohibition around the tenth street, perhaps (7)'
• Drunk obtains support that adds to one's defences
• French good to guard Italian wine in fortress
• It's fortified wine that's good for Parisian to drink
• Good French wine is kept in stronghold
• Defender of Italian wine kept in bond, for the most part
• Improperly obtains part of castle that's outstanding?
• Defender of good French wine must be drunk