Preheat your oven to 200°C/180°C fan (390°F/355°F).
Tip your nuts onto a baking tray. Roast for 5-7 minutes, tossing half-way through, until they are starting to turn golden brown. Leave to cool and roughly chop.
Heat a small frying pan over a medium heat. Add in your mixed seeds and toast for 1-2 minutes, tossing frequently. Take off the heat and set aside to cool.
Break your chocolate into chunks and either melt in the microwave or in a bain marie.
Once melted, take off the heat and stir in the olive oil.
Add the nuts, seeds, dried mango, goji berries, and sultanas into a bowl. Stir through the chocolate.
Line a small loaf tin, around 6cm x 13cm. Tip the mixture into the tin and smooth the top with a spatula.
Refrigerate for until solid, around 2 hours.
Slice into 1cm pieces. Keep in a sealed container in the fridge for up to 1 week.