Blend the mango is food processor to a fine purée.
Pass the purée through a sieve and add the xanthum gum. Pour the mixture into a shallow tray (it should be about 1cm/½in deep). Chill in the fridge for 1-2 hours, or until set. Cut into 1cm/½in cubes.
Heat the shallots, white wine vinegar and white wine in a saucepan. Bring to the boil and continue to cook until the volume of the liquid is about two tablespoons.
Add the cold water and reduce again until the volume is about one tablespoon.
Reduce the heat and whisk in the butter, a cube at a time.
Remove the pan from the heat and pass the sauce through a sieve into a clean saucepan. Add the chives and season to taste with lime juice, salt and freshly ground black pepper.
Lightly season the scallops with salt and freshly ground black pepper then rub with the olive oil.
Heat a frying pan until very hot, add the scallops and cook on either side for 45-60 seconds then remove from the pan and set aside to rest for a couple of minutes.
Meanwhile, for the pickled vegetables, bring the vinegar and sugar to a simmer in a saucepan.
Place all the vegetables into a bowl then pour the vinegar mixture over the top. Stir until combined, then set aside to pickle for at least 2 hours.
To serve, scatter the vegetables over the serving plates then add three scallops to each plate. Place squares of mango jelly in between the vegetables. Scatter over the coriander cress and mint leaves then finish with a drizzle of sauce.