Preheat the oven to 180C/350F/gas mark 4. Spread the oats, pumpkin seeds and golden linseeds out in a roasting tray and toast them in the oven for 8-10 minutes until just starting to turn golden and fragrant. Remove from the oven and set aside to cool.
Line a 26cm/10in square tin with baking parchment, leaving some overhanging on either side.
Tip the cooled oats and seeds into a large bowl along with the puffed rice cereal, almonds, chia seeds, dried cranberries, apricots and goji berries, mix everything together.
Place the coconut oil, sugar and honey in a pan, heat gently until the sugar has dissolved then bring up to the boil and allow to bubble for a minute. Remove from the heat and stir in the cinnamon and salt then pour over the oat mixture, stir until everything is well combined. Allow to cool for 10 minutes or so until the mixture is no more than barely warm, then stir through the chopped chocolate.
Tip the mixture into the prepared tin, spread it out into an even layer then pack it down very firmly; use the base of a glass to help you to press it down. Place the tin in the fridge to chill for about an hour until completely cold.
Use the overhanging parchment to lift the slab out of the tin then cut it into twelve slices using a very sharp serrated knife (slice it into quarters the cut each quarter into three strips.). Wrap each bar individually in clingfilm and store at room temperature for up to a couple of weeks, or in the fridge for up to a month.