Problem with Pear Tree Leaves

Hi I have a number of Apple and Pear trees that are in the 2nd year since planting them in my garden.  All my trees are very health except one Pear trees, which has some strange things on some of the leaves.  I have uploaded a few pictures to help.

 Can anyone identify what is going on with the tree (and leaves) and suggest a solution.

Thanks

Richard

It could be blister mite. Details and pictures here, along with treatment options.