Thanks very much Mr Karrot, Loverboy, Frederick, Jayjay and revoL annaerB.
Natasha really wanted those particular jeggings and those ones in particular always sold out really quickly, very frustrating but we manged to get some in the end.
We managed to get them from this place:
http://www.purediva.co.uk/leg-wear-13-c.asp along with some other bits and pieces.
In case any of you lovely dolls or doll owners are looking for alternative leg wear, a search for 3D printed leggings on ebay brings up a ton of very interesting ones, even spotted some cool star wars leggings with C-3PO and R2-D2!