The capitol release is not on 45cat yet, its 1961 and I don't think UK acts were being promoted that well by Capitol generally. Same would probably apply on London to their 'Rock' acts - I expect Frank Chacksfield / Mantovani probably sold more for British Decca out there.
Cliff Richard too never got USA. Its the way in which the music industry was arranged out there, plus strong competition of USA home brewed artists. Weren't there some USA acts that never made it big in the States, but did in the UK ?
" Don't Treat Me Like A Child " was a no.4 U.K. hit in 1961 for 14-year old London school-girl Helen Shapiro. It is a very catchy , mid-tempo song , with " teenage " lyrics , set to an attractive arrangement. Shapiro had four other U.K. hits , including two number ones , but I think that this record ( her first ) was her best. None of her records charted in the U.S. , apart from one week at no. 100 with " Walkin' To Happiness ". Today , at the age of 67, Shapiro still performs , but only gospel music.