Preheat the oven to 150C/ 300F/ GM 2. Divide the 60g of butter into 4.
Cut the venison into small chunks and toss in the flour.
Peel the onions and wipe the mushrooms clean. Chop larger vegetables in half.
Melt ¼ of the butter in a casserole dish over a high heat and tip in ⅓ of the meat. Brown it all over, then remove with a slotted spoon.
Repeat the above step twice more, using another ¼ of the butter and ⅓ of the meat each time until it is all browned.
Melt the remaining butter in the pan and add in the bacon. Cook, stirring frequently, until browned & crispy. Remove it from the pan.
Pour the red wine into the pan. It will bubble and reduce, but stir it to deglaze the pan.
Add the venison, bacon, onion, mushrooms, salt, pepper, minced garlic, bay leaves and thyme along with the stock. Scrape in any leftover flour from the bowl the venison meat was toss in. Stir.
Bring the contents of the casserole pot up to simmering point then cover and transfer to the oven. Cook for 1½ hours, then stir and cook for a further 1½ hours. Test the venison at this point. It should be nicely tender. If not, cook for an extra 30 minutes.
When the meat is cooked, remove it from the oven and spoon the pie filling into a large sieve suspended over a bowl to catch the gravy. Set aside to cool completely. (Once cold either use to fill the pie or refrigerate until ready to proceed.