Brown worm like marks on cherry tree leaves

Hi, 

Id be immensely grateful if anyone could help me work out what's happened to our new cherry tree (morello). It's developed these strange worm like brown marks on the leaves, and a lot of the leaves are subsequently looking a bit burnt. I wondered if it was cherry leaf spot, but none of the pictures I can find online describing cherry leaf spot look similar to whats happening to our tree. Hopefully someone out there has seen this before and can identify it for me. 

Many thanks in advance! 

malcolm