Aston Martin DB11 Owner's Handbook Manual page 72

Top Tether
The tether anchor point for the passenger seat is located at the
rear base of the passenger seat. Move the seat forward to access
the tether anchor point. Route the tether strap through the
opening in the seat back as shown.
Engage the tether clip to the anchor point at the bottom of the
passenger seat back (A) and make sure that the locking spring has
fully closed to prevent accidental disengagement. Always make
sure that the tether strap length is adjusted to remove any slack.
The tether anchor adjuster (B) must go through the opening.
Any adjustment must be made from the rear of the seat.
3.26
Before Driving
Rear Child Seat Installation
The rear seats for this vehicle use a Child Restraint Anchor System
(CRAS). CRAS consists of both lower fixing anchors and a top
tether to safely secure a child seat into a vehicle seat.
Warning: An unsecured child seat is dangerous. In a
sudden stop or a collision it could move, causing serious
injury or death to the child or other passengers. Make sure
the child seat is correctly secured in place according to the
manufacturer's instructions.
Warning: When installing the child seat, make sure that
there are no seat belts or foreign objects near or around the
CRAS anchors. If seat belts or a foreign object prevents the
child seat from being securely attached to the CRAS anchors,
the child seat could move in a sudden stop or collision
causing serious injury or death to the child or other
passengers.
Warning: The child seat top tether must always be used
when installing a child seat with CRAS anchors.