For the red cabbage purée, heat a large saucepan, add the butter and red cabbage and fry for 1-2 minutes, or until just softened.
Add the red wine and bring to the boil. Reduce the heat until the mixture is simmering and cook until the volume of liquid has reduced by half. Add the remaining ingredients and bring to a simmer. Cover and continue to cook for 40-45 minutes, stirring occasionally, until tender.
Remove the lid and cook for a further 5-8 minutes over a high heat, or until the liquid has evaporated and the red cabbage is slightly sticky and glossy. Season, to taste, with salt and freshly ground black pepper.
Allow to cool slightly then transfer to a blender and blend until smooth.
For the venison, preheat the oven to 200C/400F/Gas 6.
Heat the oil in a small ovenproof frying pan. Season the venison with sea salt and freshly ground black pepper and add to the pan. Fry quickly on all sides until lightly browned. Transfer to the oven to roast for 6-8 minutes, or until cooked to your liking. Set aside to rest before serving.
To make the sauce, heat a saucepan and add the butter. Once hot, add the shallots, garlic and thyme leaves and fry for 1-2 minutes, or until softened.
Add the rest of the ingredients, apart from the blackberries, and cook for 5-8 minutes, until reduced in volume. Just before serving pass through a sieve and add the liquid back to the pan and add a knob of butter and the blackberries.
For the celeriac and baby beetroots, preheat two small frying pans. Once hot, add the oil and butter. Add the celeriac to one pan and the baby beetroots to the other and cook both for 6-8 minutes.
For the potato galette, heat a small frying pan and add the butter, once melted place the spiralized potato in the frying pan. Cook on both sides for 3-4 minutes, until crisp and golden-brown.
To cook the kale, heat the butter in a frying pan then add the kale and two tablespoons of water and cook until the kale is wilted down.
To serve, place the red cabbage purée on the plates with the potato galette. Put a spoonful of the kale on top. Once the venison has rested cut it into pieces and put on the plates.
Place the celeriac and beetroots around the plates and spoon the blackberry sauce over the top.