AngularJS filter on multiple lists of multiple checkboxes

I apologise if this has been answered already, but I'm new to Angular so might have missed it.

I have a need to provide multiple sets of checkbox lists, which need to be combined to create an AND query.

It's on Plunker here http://plnkr.co/OGmGkz22n4J4T8p74yto but enclosed below. At the moment I can select the bottom row and the correct names appear from storeArray, but I cannot work out how to add the Format array into the filter.

I've tried:

<div ng-repeat="store in storeArray | filter:(formatFilter && tillFilter)">

and

<div ng-repeat="store in storeArray | filter:formatFilter:tillFilter">

but they don't work.

Any suggestions please?

var myApp = angular.module('myApp', []);

function MyCtrl($scope) {

  $scope.formatFilter = function(a) {
    for (var fmt in $scope.formatsArray) {

      var f = $scope.formatsArray[fmt];

      if (f.on && a.format.indexOf(f.name) > -1) {
        return true;
      }

    }
  };

  $scope.tillFilter = function(a) {
    for (var till in $scope.tillsArray) {

      var t = $scope.tillsArray[till];

      if (t.on && a.tills.indexOf(t.name) > -1) {
        return true;
      }

    }
  };

  $scope.formatsArray = [{
    name: "Super",
    on: false
  }, {
    name: "Express",
    on: false
  }, {
    name: "Other",
    on: false
  }];

  $scope.tillsArray = [{
    name: "Main",
    on: false
  }, {
    name: "Service",
    on: false
  }, {
    name: "Petrol",
    on: false
  }];

  $scope.storeArray = [{
    "id": "1",
    "name": "101",
    "format": "Super",
    "tills": ["Main", "Service", "Petrol"]
  }, {
    "id": "2",
    "name": "102",
    "format": "Express",
    "tills": ["Main", "Service"]
  }, {
    "id": "3",
    "name": "103",
    "format": "Other",
    "tills": ["Main", "Petrol"]
  }, {
    "id": "4",
    "name": "104",
    "format": "Super",
    "tills": ["Service", "Petrol"]
  }];

}