We found our Thetford Porta Potti 145 way too low. To make it easier to use I added a 120mm platform to match the height of our toilet at home. No doubt there are a number of ways to do the same job.

Using 12mm plywood I cut two lengths the width of the portable toilets diagonal length adding stoppers on the end. Two slots were cut to allow them to join together & pull apart to pack flat in the camper trailer.

I used an old tent peg & a bit of steel angle to make a brace to lock the two parts of the platform in place.