Preheat oven to 350ºF. Line a large oven dish or tray with greaseproof paper or foil.
In a large bowl add the rolled or jumbo oats. Add the nuts and seeds.
Measure out the peanut butter into a microwavable bowl and heat for 30 seconds. Stir and add the honey. Stir thoroughly and heat for a further 30 seconds.
Mix until smooth and pour into the mixing bowl with the oats.
With a wooden spoon, mix together all the ingredients thoroughly. You should aim for the dry ingredients to be thoroughly and evenly coated with the sweet nutty sauce.
Pour into the prepared oven tray.
Bake in a preheated oven for 20-25 minutes. Stir and gently toss every 5 minutes to avoid anything burning.
Allow to mostly cool before serving.