In a large bowl, mix the wholemeal flour, semolina and salt together with the sesame, flax and ground pumpkin seeds.
In separate bowl, whisk 210ml/7¼fl oz water with the honey and oil. Stir in to the dry ingredients and mix to a medium-firm dough.
Knead the dough for five minutes. Return to the bowl, cover and set aside for 20 minutes.
Preheat oven to 180C/375F/Gas 4. Line 2-3 baking trays with non-stick parchment.
Oil the work surface and roll the dough out to a thickness of 3mm.
Using a ruler and a sharp knife or pizza cutter, cut the dough into rectangles or diamonds, of approximately 5x15cm/2x6in. Place on to the prepared trays close together, but not touching.
Spray the crackers with water. At this point you can add a topping if you wish (more ground seeds or spices). You can reknead any left-over scraps, but they will not be as successful as first kneading. Alternatively, put the scraps on a tray and bake them for snacking.
Bake the crackers for 15-18 minutes. Turn the oven off, open the door for 30 seconds and close again. Leave the trays in the residual heat of the oven for 10-15 minutes for extra crispness. Transfer to a wire rack to cool.