If you get it via Ebay; the plant will be acompanied by a phyto certificate and the UK customs official recognizes it especially if it comes from a reputable seller. The USA and UK have a well established plant and agronomical forreighn relations.
But shipping to the UK is hurtful to the pocket...I ordered some rare English roses from England and it arrived to me well packed healthy specimens...but the UK mailing is kinda steep...I could have bought ten plants in the USA with that shipping amount LOL
I've purchased from Seed Engei both directly and on ebay, decent plants for the price, great selection and great to deal with, although I thought Satomi was a female?