Nigella's Lamb and macaroni stew

Here's another one of Nigella's recipes, taken from the episode "Weekend". What I simply love about her receipes are that it's so simple and fool-proof, anyone can do it! Now if only I could work up the effort it takes to do so! (transposed to the best of my memory) Nigella added that with any stew, it's just something thrown together rather rustically, so no need to over-fret over the proportions and amounts, just something reasonable would do!

Ingredients (feeds 6 to 8)
Lamb shoulder, cubed (enough to feed 6 to 8, heck if I know how much!)
2 to 3 stalks celery, chopped
1 carrot, roughly chopped
3 tins canned tomatoes
Oregano
A few bay leaves
Roughly 1 cup water
1 large onion, peeled
2 to 3 cloves fat garlic, crushed and paper removed
Salt and pepper for seasoning according to taste
Oil for browning

Method
1) Brown the cubes of lamb. Remove onto another dish.
2) In a processor, blitz together the celery, garlic and onions. Pour into the pan with the left over oil from browning the lamb. Let soften for about a min (but don't brown).
3) Remove half of the mixture. Flatten out the remaining mixture into the plan.
4) Pour back the lamb. Pour back the onions on top and cover the lamp. (Nigella does because she says that she finds that the mixture helps to seal in the moisture of the lamb)
5) Pour in the 2 cans of tomatoes, and 1 cup of water.
6) Sprinkle over the oregano and bay leaves.
7) Cover and simmer on low heat for 2 hours. Alternatively, transfer to a low oven for 2 hours.
8) It will be a bit watery, but this is used to cook the macaroni. When the stew is ready, pour in the macaroni to cook. Season with salt and pepper.
9) Serve when macaroni is cooked.
10) Nigella also uses feta, roughly mixed by hand together with chopped fresh oregano and serves this on top of the stew.