Potato and cheese pie

I tried out this recipe from a magazine. Not sure about it - see comments

Ingredients (for 2 people)
self raising flour
butter
water
onion
peeled and sliced potato
grated cheese

Equipment

saucepan or frying pan
mixing bowl
rolling pin
pie dish

oven:
time in oven: 40-50 mins, plus let it stand for 10 mins

preparation time:
making dough
fry onion and potato
construct pie

. Add enough water to make a soft, but not wet, dough.
Fry the onion in a little butter until soft.
Peel and slice the potatoes very thinkly, add them to the onion and fry them for a few minutes.
Grate the cheese.
Roll out two thirds of the dough into a rectangle big enough to line the pie dish. Use extra flour to stop things sticking. Put the pastry into the pie dish. It should fit the bottom and overlap the sides.
Fill the pie with layers of potato and onion, then cheese, etc.
Roll out the rest of the dough into a rectangle, and lay it on top of the pie. It isn't too important to seal the ewdges firmly, as the contents of the pie are solid, and shouldn't leak.
Put in the oven, and cook until light brown.

This is rather a lot for two people. The original recipe said that the portions were generaous, and they certainly were.
The potato was under-cooked. You could deal with this problem by boiling the slices a bit beforehand.
It was a bit bland, but even so, I wasn't sure about the onion. Perhaps the combination with the cheese made me think of cheese and onion crips, which I never liked! The original recipe added some mustard, which also didn't seem to fit. Perhaps it would be better to have just the potato (pre-cooked a bit) and the cheese, and add your own flavourings when eating it. We used brown sauce.
The pastry, on the other hand, was very nice! It seemed odd for use self raising flour, but it did make it more open, without having the texture of cake (which I was worried about). The proportions of 2:1 of flour and butter does make it very easy to scale up and down. And no egg to complicate matters! (Eggs are quantised...)