Anyone Know What This Insect Is?

.......... the best I can come up with is some kind of Digger Wasp but I'm really not sure.
There were several of them hovering about an inch or so ( 2-3cms) above the lawn and looking interested in any tiny holes in the lawn.
Sorry it's a rubbish photo but they wouldn't sit still for more than half a second.
I just want to know if I should be concerned about them being there as I've never seen one like this before.