Nannytopsy
I have had disappointingly small plants from Parkers and always say I won’t use them again. Sarah Raven are overpriced and seeds show poor germination. I bought dahlias last year, some of which were very small tubers. I am trying to use some of our local nurseries, which have interesting plants.
JParker’s plant descriptions clearly state what size they are Nannytopsy, if you order plug plants they are tiny, but obviously cheaper. I always order garden ready size, which are more established, bigger plants which have never failed for me. I think the devil is in the detail of your order, true for all companies unless you order very late and end up with a more developed plant, but more likely to be pot bound.