Place the apricots in a bowl with boiling water and leave to soak for at least 2 hours, then puree in a blender or food processor.
Preheat the oven to 356ºF (180ºC ) Toast almonds, walnuts and oats in a oven for 15 minutes.
In a small saucepan melt the butter and honey over a medium heat.
Place the toasted almonds, walnuts and oats in a food processor and pulse until the nuts are loosely chopped. Place the apricot puree, cranberries, lemon zest,oats, nuts and butter-honey mixture in a bowl and mix well. Line baking tin (8×4 in) or other small pan with plastic wrap. Tip the mixture into the lined tin, spread out in a even layer. Cover with plastic wrap, and let set in fridge for 2 hours minimum or overnight.
Remove bars from tin and cut into 6 bars. Store in air-tight container for up to six days.