Lightly oil and season the husked corn cobs with veg oil, salt and pepper. Grill until lightly charred. Cool grilled cobs and remove kernels with a knife. Reserve kernels and 2 of the cobs. If using frozen corn kernels allow the kernels to thaw, pat dry, season with veg oil salt and pepper. Spread evenly on a baking sheet and roast in a 350F oven until golden brown.
Add the bacon to the bottom of a large heavy soup pot set over medium heat. Stir until the bacon is crisp, 4 to 5 minutes. Remove to a paper–towel–lined plate with a slotted spoon. Add the butter and once melted, toss in the garlic, celery, carrots and onions, and sauté until nice and tender, about 6 minutes. Season the mixture with salt and pepper and sprinkle in the flour and stir until lightly colored and pasty; another 2 minutes. Slowly pour in the chicken stock and then stir in the grilled or roasted corn kernels, potatoes, reserved 2 husked cobs if available, thyme and bring to a boil. Reduce the heat to a simmer and cook the potatoes until just tender, stirring occasionally, 15 minutes.
Pour in the milk and cream and simmer for 20 minutes more. Taste for seasoning and adjust accordingly before serving.