Here Gaz take a look.
The bars on the side are what bolt on to the side of the trailer - obviously with yours you need to have them higher with 2 bars either side dropping down to come level with the top of your tank.
We can make these for you but delivery might be a bit high.
The end bars are angle iron, the lateral bars are box section 30mm. We then cover them with steel sheet, prime it, spray it, lacquer it. Job done.
Patent Pending