Today I have made the same recipe just swapping out the flour for gluten free flour, plain in this case from Marks & Spencer (I can't find it in their webstore to link to) & I used gluten-free baking powder too.
The cake batter looked exactly the same as usual, same consistency, etc
& baked just the same - I think I was thinking that the batter & cake consistency would possibly be drier but not so, the cupcakes came out just lovely!! And they taste really chocolately & light, not as light as usual but the non-gluten free recipe is very light anyway. The family gave them the thumbs up especially once they were topped with a lovely big squidge of extra chocolate icing! Infact, my husband said if he didn't know they were gluten-free he would not have known. So thumbs up all round!