I suspect that the turnout will be above average, especially for Euro Elections (especially since the only recent time they weren't held at the same time as the Locals turnout was just 24%).

Every time I vote I always ask the teller what turnout is like. When I voted in the locals last time he said it was slow, I was voter number 50 (for my ward). Today at same time he said it had been brisk, I was voter number 74. 50% increase.