I believe your grab handle will suffer and will wear underneath that bracket. A mount like this would be much better.
https://rammount.com/products/ram-vb-195-sw2
Someone has to figure out where to mount it best. Maybe on the screws of the fire extinguisher? But then it would eventually restrict the movement of the seat. Ideal would be if the bracket was mounted on the seat itself so it would slide back and forth when the seat is adjusted.