Boil the potatoes in their skins for 15 mins until tender, then drain and cool. Meanwhile, whisk all the sauce ingredients together, except the dill. Cut each piece of salmon in half to make two long strips.
Halve the potatoes slightly on a diagonal, then wrap a piece of smoked salmon around each piece and place onto a platter. If you want to add salt, go easy, as the salmon is highly seasoned.
Scatter with pepper, a squeeze of lemon and a few dill fronds. Give the sauce a quick whisk, add the chopped dill, season to taste, then pour into a dipping bowl. Scoop the lactose free cream mixed with the lemon juice into another dipping bowl. To eat, dip the potatoes into the cream, then spoon over a little sauce.