Received no reply here. Found no manual with a description. Nothing to do except start removing bolts until the seat comes out. Prior experiences indicate I will probably remove a few more than necessary until it is figured out.
Seat Extraction Procedure:
I decided to take the smaller of the two seats out of the Blazer rather than the large.
However the procedure looks to be exactly the same for either.
From the front of the seat remove the plastic covers and remove the two 15MM bolts.
Move the seat all the way forward.
At the back base there will be one visible T50 star bolt. Not a common wrench type so you may need to get star wrenches going up to size T50.
Remove the bolt using the star wrench.
On the other side is a plastic cover over the other bolt. Remove the cover using a T25 star wrench, pop the plastic cover. Remove the other T25 holding the plastic cover.
Remove the T50 bolt holding the seat.
Remove the plastic cover where the bolt was.
The seat is now lose from the floor, tilt it forward and prop it up so it doesn't fall on you. There is a cable running from the seat to the release at the back of the car (used so you can drop the seats from back at the hatch - i hadn't even noticed that before) Under the seat is a felt pad. the cable runs from the seat to a connector under there and then to the back of the car.
Remove the seat cable from the connector. There is a piece to squeeze which moves the piece with the arrow ( in the opposite direction of the arrow!) Disconnect the cable like you would a bike cable. You can now remove the seat from the Blazer. Recommend putting all those parts in a plastic bag an securing it to the seat during storage...