Preheat the oven to 160C / gas mark 3. Grease and line a baking tin, about 20cm square.
Put the butter, sugar, peanut butter, honey and grated citrus zests in a deep saucepan over a very low heat. Leave until melted, stirring from time to time.
Stir the oats, dried fruit and three-quarters of the seeds into the melted butter mixture until thoroughly combined. Spread the mixture out evenly in the baking tin, smoothing the top as you go.
Scatter the remaining seeds over the surface and trickle with a little more honey. Bake for about 30 minutes, until golden in the centre and golden-brown at the edges.
Leave to cool completely in the tin (be patient it cuts much better when cold), then turn out and cut into squares with a sharp knife. These bars will keep for 5-7 days in an airtight tin.