A slight hiccup – I missed a couple of points. Truth to tell I’m not too well right now.
First, if you want this as either a pie filling or a casserole, the same directions apply to both.
After that you can either combine and heat several portions, then put in a pie dish and cover with the crust of your choice (I favour suet crust). Or you can tip it out of the individual foil dishes, heat, and return it, and top each dish, first folding down the edge, with a crust.
If you want the sauce to be thicker, the simplest way is bring it to the boil and stir in a tablespoon of Smash per portion.
The other thing is, after browning the meat, tip the oil and butter into the casserole pot, adding a little more if needed, and sweat off the alliums in that – no point in wasting all that flavour.
You can reclaim more by deglazing the frying pan with half a pint of hotwater – bring it to the boil and let in bubble while scraping up anything clinging to the bottom and sides with a wooden spatula. Add that to the pot, too.
And for labelling the foil dishes, not just for this but for everything I freeze in individual portions, I find Avery shipping labels No. L7165 (packs of 40 sheets, 8 labels to the sheet), ideal. Big enough for ample information, robust enough to survive the freezer. £10 to £12 a pack, but shop around, the price varies. Try Amazon.
Now you really are done.