If you had given the US number it goes by ie #4 which is worsted weight. This number is always on the ball band or on the pattern you are going to do. But if an American member reads your post who knows what it is, you should get an answer.
there must be a lot of lace or fancy patterning to the garment for it to use that much yarn or it maybe just double yarn through out the pattern then that means that you should be able to use 8ply/double knit/worst #4
are you able to post a picture of the jacket and hat I would love to have a look at it.
http://www.craftyarncouncil.com/weight.html see if this helps, I would think it is your fingering yarn. Here in the US it is a catagory #3 yarn. Used for many baby items. Have you looked at their web site for patterns using this yarn.Bernet has a site you just need to make a pass word and lots of free patterns. Enjoy and good luck.
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