Very good picture but unusual for mother to leave chicks and eggs unguarded.
You did'nt scare her away by any chance, if you did then the chicks will be vunerable to other Gulls.
No we did not scare them away, where they are nesting, anything that comes near where they are nesting on the farm, they tried to scare us away, lol but all is ok, gulls did not abandon the nests.
You did'nt say what type of gull they were.
My guess at the moment would be Blackheaded.
This bird nests on the top of Hering Gull stack at Lybster every year.