Primark love to lounge nightwear sizing-is it on the generous side?

[Madaboutthrows]

I ought some of the ribbed pj bottoms with lace on the legs and I am planning on buying a few more pairs. The pair I have is medium and I am wondering if its worth going for the small.

Is the sizing generous?

I'm a size 10 and usually buy the small in Primark pyjamas.

DD wear primark PJs in a small and she is size 8-10