Use kitchen scissors to trim any excess fat off the mutton, then cut into pieces about an inch large.
Put the mutton into a medium or large pot and add enough water to cover the mutton plus a couple inches on top.
Bring the liquid to a boil. Icky fat bits should float to the top after the boil, so use a spoon to scoop it all out and discard.
Destem and deseed the scotch bonnet pepper then chop into pieces and add to the pot.
Also add to the pot the pimento seeds, salt, pepper, thyme, and the pumpkin. Stir.
Reduce the heat to medium-low and simmer for about 1 ½ hours.
Peel the yam and potato and chop into pieces about an inch large. Chop the cho cho the same (no need to peel it though).
Finely chop the onion and garlic. Chop the tomatoes and carrots into chunks.
Add all the remaining ingredients after 1 ½ hours of the meat on the stove. Continue simmering for another 30-60 minutes or until the potato is soft enough to cut through with a spoon.
Depending on how you like your soup consistency, you can add more water for a more brothy soup, or you can turn the heat up and allow some of the liquid to evaporate, leaving you with a thicker stock.
Spoon into bowls, garnish with a sprig of thyme, and serve.