Why won't my cream biscuits rise? I am trying to make these "cream biscuits". However, they just will not rise (tried 4 times) and end up looking very flat.

I thought my problem was that I work the dough too much, but I tried it again and didn't touch the dough much but it still doesn't rise. I am using newly bought baking powder.

I am thinking the problem might be one of these reasons:


I used double cream instead of heavy cream because I am in
the UK and we have single/double but not "heavy cream". (I just
found out heavy cream is whipping cream in the UK)
The first batch was made with the full recipe and none of them
    rose, so I experimented by cutting everything by 1/4 and made 2
    biscuits at a time.


Why won't my biscuits rise? Are there any other possibilities?
The recipe is fine; if you follow it carefully it should work. Things you might mess up:


Baking powder isn't baking soda; make sure you have baking powder.
If you leave the dough alone for hours before baking, the baking powder will expend itself.
It's silly, but make sure you used a tablespoon of baking powder, not a teaspoon.


Working the dough longer won't help - if anything it'll make the biscuits tougher. And double cream is a bit more fat than heavy cream (see this question), but it shouldn't be a big deal.