I’m, this might have itching to do with it, but, just a thought, or two.
Have you checked if it is the US or UK sizing on the needles? (I don’t even know if this is what they are called and I am sorry if this is incorrect terminology.) I really don’t know much about it other than they are different sizes.
Also did you check the yarn you are using is correct for the pattern? Perhaps if it is thicker than the pattern requires then your swatch will come out bigger?
Otherwise, I think I’d choose a different pattern with needles you are comfortable with.
Hope you work something out.