Squidward, did the same to my own 110. Back rest had metal brackets that fitted up into the rail around the tub at the top and bolted down into the wheel boxes. Had to drill out me own holes, and used 3mm backing plate to hold them down. Seat part just folds up. Not yet fitted seat belts (not sure that lapbelts on sideway facing seats are really useful) but if do will bolt down onto chassis somehow. Happy to supply pics if it would be helpful.