Magnum selection is a bit shit out here, but I am partial to the Almond Magnum.
And the London Dairy Mango or Raspberry Sorbet.
But otherwise I mostly order the cake fudge Sunday from a local joint called Corner House, two scoops of rum n raisin (usually comes with vanilla but I ask for rnr) with basic chocolate sponge cake on top, covered in hot chocolate fudge and peanuts.
In England, I used to love the Orange Calippo.
