I decided to use this rectangle tin I had rather than a glass bowl and it turned out perfectly. The kids loved it and I loved it although the whole process takes a while from organizing the pastry, cooking the leek and bacon, grating the cheese and mixing the eggs and milk together. It feels like it takes half a day to cook and then we sit down to dinner and it's eaten in 5 mins. The recipe made the large tin plus a single little serve which I cut in half for the kids to take to school today for lunch.
The recipe came from here.