I found the ingredients at Cost Plus, but if you can't find Maltesers, you can use Whoppers. Graham crackers can stand in for digestive biscuits, and dark corn syrup will work in place of golden syrup.
Malteser Tray Bake
(adapted from Nigella.com)
1 stick butter (1/2 cup)
3 tbsp golden syrup
1 cup milk chocolate chips
13 digestive biscuits, finely crushed
8 oz Maltesers
Melt the butter, syrup, and chocolate chips together in a medium saucepan.
Stir in the crushed biscuits and Maltesers, and mix well.
Pour into a greased 13 x 9 pan and chill until firm.