I would like to make a dish with mash/creamed potatoes.
maybe have a cream based sauce & finally what veg would you recommend

Watch those colors. So far you are very white. Get green, red,
brilliant yellow onto that plate. You might also run the potatoes
under the broiler with some buttered crumbs on top to give them a tan.
I love monkfish. Here it is called lizard tail, not very appetising.