St George was a saint, not only for Christians in the Holy Land but also for Muslims and Jews as well. A figure of unity.
That he is not only a saint for Christians is very crucial. If you go to Al-Khader (near Bethlehem), you will find a church and monastery of St George, which is predominantly visited by Muslims. Also in Lod it is not only the church that is dedicated to St George but also the Mosque next door, Jamia al-Omar, one of the oldest mosques in the region. To Muslims he is very holy and Al-Khader, or the "green one", is the name they use for St George.
So there is no reason why they wouldn�t celebrate it, I imagine many of them met it with as much gusto as your average British Joe.