Preheat the oven to 160°C/ Fan 140°C/ Gas 2. Pour half the olive oil into an ovenproof dish or Dutch oven, gently warm, add the bacon lardons, cook for 4 minutes and remove from the heat.
Put the diced venison and flour into a bowl and toss well; once coated, shake off any excess flour, then place the ovenproof dish back on the heat and brown the venison in the pan.
Add the rest of the oil, garlic, shallots and celery and cook for 1-2 minutes, then add the carrots, mushrooms and herbs; cook for 15 minutes, add the wine and bring to the boil.
Add the beef stock, season with the salt and pepper, place the lid on the top and cook for 1 ¾ - 2 hours in the oven until the meat is tender.
Remove from the oven and strain the meat and vegetables using a sieve, keeping the liquid. Put the liquid back in the pan and bring to the boil on a medium high heat (on the hob) to slightly reduce and thicken. Whisk in the redcurrant jelly, butter and chocolate, then pour over the venison and vegetables. Serve it with mashed potato or crusty bread.