Apple pest ID

Here's a couple of pictures of a new apple tree we were given as a present. Planted this year, keeps well watered and I took all the fruitlets/ flowers from it to keep its energy in getting established. Now on the younger leaves especially I've found this. There is also ant  activity around the leaves but we have loads of ants so I wasnt greatly surprised about that. Any idea who these fellas are and how to get rid if needs be?