I have found this recipe, but I want to use dry active yeast, rather than easy blend. My question is can I proof (right word?) the yeast in the milk? and how much should I use?
Yes, you can proof the yeast in the milk. Heat the milk gently to around 120 degrees F (use an instant read or candy thermometer to check). I would use all the milk.
You CAN proof the yeast in the milk, but if you do, be careful not to get it too warm. Think baby bottle on wrist temperature.
Note that if your yeast really IS Active Dry Yeast (you haven't had it above your stove for the last 3 years), you can probably just dump it in. It might take it a little longer to come around, but yeast is very resilient. I tend toward the overnight in the refrigerator method of bread making, longer slower growth by the yeasties.
Another thought, if you really need the yeast to move fast, you can kick it up a little bit, assuming you have yeast in bulk. The only reason why your recipe is calling for 2 teaspoons is because that is how much comes in a packet.
Easiest is just to dump it all together and make sure that your dough has time to rise, no matter how long that takes. When I make sourdough bread, it can be all day, but if it is alive, it always rises.