I found these two pictures which claim to be early costume tests from the In the Night Garden pilot, presumed to be made around 2006. Although it's said the show was already in production from early 2005 so this date is most likely incorrect. There's no sources that these images are indeed related to the pilot, but from the look of it it's certainly plausible, as Makka Pakka has more fluff and Upsy Daisy appears to be lighter skinned and her hair is straighter.
On another note, the Teletubbies pilot is also likely out there somewhere although I couldn't find anything of it, but most shows have a pilot and considering how popular Teletubbies is it wouldn't surprise me if a pilot was a desired item.