Ham and Corn Chowder with Potato

Name: Ham and Corn Chowder with Potato
Ingredients: 1 1/2 cups ham (, roughly chopped (Note 1)); 1/2 tbsp olive oil; 3 tbsp butter; 1 garlic clove (, minced); 1 small onion (, diced (or half large onion) (yellow, brown or white)); 2 potatoes (, peeled and diced into 8mm / 1/3 cubes (Note 2)); 1 1/2 cups frozen corn ((or drained canned corn)); 5 tbsp flour; 2 cups milk ((I use low fat but full fat will work too)); 1 cup chicken stock; 1 1/2 - 2 cups water; 1 1/2 tsp fresh thyme leaves ((or 1 tsp dried thyme), plus extra for garnish); 1/2 tsp salt; Black pepper