Heat the oil in a large pan. Add the lamb (or mutton) and cook until browned on all sides.
Add the onions and chilli to the pan and cook until softened.
Meanwhile, make up a jug of stock with the three beef stock cubes and about 900ml/1 pint 12fl oz of boiling water, according to taste. Add the stock to the pan and simmer for 40 minutes until the meat is tender.
While the soup is simmering, chop the yam, butternut squash and potato into pieces.
Heat the chicken noodle soup in a separate pan add the yam, butternut squash and potatoes. Cook the vegetables until tender. When they are cooked all the way through, drain and reserve the liquid.
Once the meat is tender, add the vegetables to the first pan and add some of the chicken noodle soup liquid if necessary.
Scatter the spring onions over the soup along with the thyme leaves.