I used the expanded dough calculating tool at http://www.pizzamaking.com/expanded_calculator.html
to convert your dough recipe to baker's percent format and got the following:
Olive Oil (5.39999%):
Milk (fresh) (5.99999%):
|500 g | 17.64 oz | 1.1 lbs|
300 g | 10.58 oz | 0.66 lbs
7 g | 0.25 oz | 0.02 lbs | 2.32 tsp | 0.77 tbsp
8.37 g | 0.3 oz | 0.02 lbs | 1.5 tsp | 0.5 tbsp
27 g | 0.95 oz | 0.06 lbs | 6 tsp | 2 tbsp
5.98 g | 0.21 oz | 0.01 lbs | 1.5 tsp | 0.5 tbsp
30 g | 1.06 oz | 0.07 lbs | 6 tsp | 2 tbsp
878.35 g | 30.98 oz | 1.94 lbs | TF = N/A
From the above table, a single dough ball would weigh 439.17629 grams, assuming that there are no minor dough losses during the preparation of the dough. That amount of dough used to make a 12" pizza translates into a thickness factor of 0.1258454. That thickness factor represents a "medium" to "thick" crust. The hydration of the recipe is actually higher than the 60% figure shown in the above table because milk contains about 89% water. On that basis, the "real" hydration of the dough comes to a bit over 65%. That's a bit high for a strong white bread flour (is it the Allinson's flour by any chance?).
In terms of improvement of the results you got, you could consider changing the recipe to make dough that is fermented in the refrigerator for a couple of days before using. That should produce better crust flavors, texture and color. To make the dough for this application, you would use cold or cool water rather than warm water and you would significantly reduce the amount of yeast. For example, a typical amount of yeast (IDY) for a cold fermented version of the recipe would be around 1.5 grams (0.30% of the weight of the flour). That would be about a half teaspoon of IDY. The dough would be divided into two pieces after it comes out of the mixer bowl and then be lightly coated with oil, placed into lidded storage containers, and then refrigerated. The dough balls should be usable after about two days, after allowing the dough balls to warm up at room temperature for about an hour and a half. You don't want to re-knead or re-ball the dough balls at that point. That will only make the dough elastic and difficult to shape and stretch out to the desired size.
If you plan to use milk, you perhaps want to reduce the amount of water in the recipe by about 27 grams. Or you can just omit the milk. At two tablespoons, it doesn't really add much to the recipe--just some calcium, a bit of fat and lactose sugar, and a few minerals. You have plenty of sugar and fat in the recipe already and any dairy note from using the milk will be overwhelmed by the cheeses. If you want a thinner crust, you can make 14" pizzas instead of 12" pizzas, if you have a 14" pan, or you can just use less dough. For example, for a thinner 12" pizza, you could use about 320-335 grams of dough.
During baking, you might want to move the pizza from the oven rack position you use to a higher oven rack position. That should give you more top crust browning.