Make your cheese sauce. First infuse the hot milk with the garlic and bay leaves. Leave for 10 minutes. Melt the butter in a pan on a low heat, then add the flour and cook out for five minutes, stirring regularly.
Pour the infused milk mixture (strain it first to get rid of the garlic etc), little by little, into the flour and butter mix (roux), stirring all the time, with the heat on low, so it will not burn on the bottom of the pan.
Then add the pepper and bring to a slow simmer for five minutes at a slow temperature, stirring constantly, before you add the cheese.
Whizz the vegetables, cheese sauce and stock in a blender, then season and pour into a large soup pot to gently heat. At this point you can check the seasoning and decide if the soup needs to be thinned a little with some more stock.