Remove the stalks from the spinach and wash well in cold water.
Blanch the leaves in a large pan of slightly salted boiling water until wilted. Remove and refresh in iced water.
Pick over the nettles and prepare as for the spinach.
On a clean, dry tea towel place a layer of spinach leaves and the larger nettle leaves to form an oblong approximately the size of an A4 sheet of paper. Cover with another tea towel and roll up. Place in the fridge till needed. (Any remaining leaves can be squeezed out and kept for a sauce or purée).
Prepare the scallops. Remove the corals (orange section)and frilly skirts. These can be reserved for use in another dish. Wash the scallops and leave to dry on kitchen paper.
Using kitchen scissors, cut off the fins of the sea bass. Remove the head and bone out through the belly. Remove the bones without separating the two fillets. (Alternatively ask your fish monger to do it for you). Remove any pin bones with a pair of tweezers and cut off the tailpieces, reserve these for another dish.
Rinse the prepared sea bass in cold water, pat dry with kitchen paper and lie flat out on cling film. Cut out an oblong of spinach and nettle and place on one half of the bass. Place a row of cleaned scallops on top of the spinach and nettle and cover with any leftover leaves.
Lift over the other half of the fish and roll up tightly into a neat cylinder. Roll again, this time in aluminium foil. Place in the freezer to chill for about 30 minutes (this will make it easier to cut).
Remove from the freezer, remove the foil and whilst still in the cling film, cut into slices approximately 3cm/1¼inch thick. Lay the slices on their sides and remove the cling film. Tie loosely with string.
Heat a little oil and clarified butter in a frying pan. Place the bass in the pan presentation side down. Season the other side and allow to dry for 45 seconds before turning and cooking for a further 45 seconds.
Season the presentation side with salt, remove from the pan and keep warm covered with butter paper. Allow to rest for about 8 minutes before removing the string and drizzling with lemon juice. Brush with the remaining clarified butter and serve.