Trim the venison, removing the skin, sinew and fat covering the meat, then tie the joint with string (you can ask your butcher to do this if you wish), ensuring you reserve all the trimmings for the sauce. Rub the venison with 1 tbs of olive oil, cover with film and refrigerate.
Heat the remaining oil in a pan and fry the vegetables with the cloves of garlic and the meat trimmings until they colour a rich golden brown. Add the Juniper, Cloves, 1 tsp of the Thyme and the Bay Leaves and pour in the red wine. Bring to the boil and simmer for fifteen minutes. Remove from the heat and allow to cool. Pour over the meat, cover again and refrigerate overnight to allow the flavours to infuse.
When the meat has finished marinating, peel and halve the pears, remove their cores and roll in the lemon juice. Place on an ovenproof tray, sprinkle with half the sugar and half the remaining Thyme, brush with a third of the butter and place under a hot grill for ten minutes. Turn the pears and repeat the process with the remaining sugar, Thyme and another third of the butter and grill until golden brown. Allow to cool.
Pre-heat the oven to 220°C, 425°F, Gas Mark 7. Remove the meat from the marinade and dry with paper towels. Season with Sea Salt and brush with the remaining melted butter. Roll the joint in the Ground Pepper and then place on a roasting tray in a hot oven and roast for 60 to 80 minutes for medium rare. Transfer the meat to a plate, cover with foil and allow to rest. Reduce the heat of the oven to low and place the pears in to warm through.
Pour the marinade into the roasting tray and heat on the stove top, scrape up the caramelised venison juices in the tray and simmer for ten minutes, reducing by half. Add the Banyuls or port and the grated chocolate, simmer for a further five minutes. Strain this sauce through a fine sieve and season with a little lemon juice and Sea Salt.
To serve, carve the venison thinly, serve with half a pear and spoon over the sauce.