My grandfather 'Jimmy' Barry was in the 1st Manx Service Company. He died in 1966. I asked him about his time in the First World war, but he wouldn't tell me much about it. My father told me that my grandfather was in the King's Liverpool Regiment, and was then transferred to the Cheshire Regiment. He was in the battles that took place near Lake Doiran. I haven't been able to find out much about the 1st Manx Service Company. I visted the Cheshire Regt museum but I couldn't find any mention of their action in Salonika. Like yourself - I'm still researching.
Best of Luck.