Heat oil in a large heavy-based soup pot on a low heat. Add garlic, onion, leek, celery, carrot, bay leaves and small pinch of salt. Cook, stirring occasionally, until onion is very soft, about 10 minutes.
Add split peas and tinned tomatoes to pot and stir through. Place hocks into pot and cover with stock. Bring to a boil then simmer very gently, stirring occasionally, covered, for about 1½ hours, or until ham comes away from the bone.
Remove ham hock from the pot, pull meat from the bone and discard the skin and bones. If you like, you can purée the soup at this stage, or just leave it chunky. Shred the meat and return to the soup.
Check the soup’s consistency: you may need to add a little more chicken stock or water if you find it is too thick for your liking.
Check seasoning, then just before serving, stir through the fresh herbs.