Blitz the Ginger Nuts in a food processor to a coarse crumb and then add the butter to combine together. (Alternatively, you can smash the biscuits up in a heavy plastic bag with a rolling pin or small heavy pan and then mix together in a bowl).
Take a non-stick 20cm springform cake tin and pack this Ginger Nut mixture into the bottom and press down well with the back of a large spoon. Chill in the fridge for an hour.
Preheat the oven to 160C.
Place the cream cheese, crème fraiche and orange zest in a kitchen mixer and whisk together for a minute. Whisk in the eggs one by one, then sift the flour into the bowl. Whisk in briefly and gently. Finally spoon the Saint Agur Blue Crème into the bowl and mix in with a gentle hand. Spoon all the mixture into the cake tin and transfer to the oven.
Bake for 45 minutes to an hour. You want it to puff up slightly and have a good golden crust. If you give it a little jiggle it should retain a jelly-like wobble. Remove from the oven and leave to cool completely.
Meanwhile place your honey in a bowl, chop the walnuts coarsely and stir them into the honey. If the honey is too thick a couple of tablespoons of warm water may need to be mixed in to make it easy to drizzle.
Finally run a knife around the inside of the spring form cake tin and then loosen the edge and carefully remove it. Cut into portion, lift carefully onto plates and then spoon over the honey walnut sauce.