Aks the fish seller to clean the fish. Cover the dorade with a very thick layer of salt. Put it in a colander and place it in the fridge. You want to place a deep plate under the collander. The fish will leak, which is what we want. What it leaks now, it can’t leak on the BBQ.
Put the fish (with its salt crust) on the bbq. Turn it around. Repeat until it’s done. Somebody once told me that the fish is done when the colour of the big bone on the inside changes to white. I never tried it, I just take a good guess.
I always use a stainless steal fish basket so it doesn't stick to the grate. And this way my friends who eat halal can eat the fish as well, while the rest of my friends eat drunken pig and hamburgers from the same bbq.