Put the chorizo, stock and vermouth in a pan and reduce by half. Whisk in the diced cold butter, and simmer till glossy.
Grill the seabass, skin side up till crisp, with a dash of oil, seasoning and a small knob of butter – for about 4 minutes.
Add the shrimp to the sauce.
To serve: Pipe a neat circle of potato puree into 4 warmed serving bowls. Neatly put the fish on top, Spoon some sauce over and around. Garnish with a few baby vegetables, and a spoon of caviar (if you are feeling extravagant!)
For the potato puree, you can use a floury potato, thinned with milk and seasoned with salt, then pureed till a bit thinner than regular mash.