Vauxhall ASTRA Owner's Manual page 78

To cover the gap between the luggage
compartment cover and the rear
backrests, there is a cover on the cartridge.
Attach the two hooks of the cover to the
head restraint guide rods. If the safety net
is mounted, run the hooks through the net
mesh.
Removing
Open the luggage compartment cover and
detach the hooks from the head restraints.
Raise release lever at right side of luggage
compartment cover. Lift right side of cover
first, then pull left side out of recess.
Seats, interior
Fitting
Insert luggage compartment cover into
recess on left, raise release lever on right
side, insert cover into recess on right,
engage and push lever down.
Attach the hooks on the head restraints -
see Fig. 17079 T.
77