THE CHAUFFEUR-DRIVEN saloon rolled up the rampart front of London's Royal Garden Hotel, out leapt the little figure in the all-white sweater and jeans and bounded up to his sixth-floor suite to relax after another day's filming with Sir Michael Redgrave and Douglas Fairbanks.     He ordered himself scotch, neat, and announced without the slightest trace of blush or broad grin: "You know, it's great to be working with such famous people, but I'm probably being paid much more than them. I'm the one the film people chased all over America to persuade to take the part."     Herman was thus explaining the latest booster rocket in his ride to top stardom - a part in "The Canterville Ghost", the film for American TV he was shooting recently with the famed Redgrave and Fairbanks.     Explaining, also, why so many people here at home resent him, Herman knows he's a fantastic success and isn't embarrassed to say so. If you call him big-headed, he replies: "You can't knock success, can you?"     He does, however, dislike the fact that he's largely disliked by other British artistes. "I don't get on well with the other groups because they resent me being so successful, but having no musical talent. But musical ability isn't particularly commercial, in any case.     "I just perform songs in my own style and when they say my style isn't hip, I always reply 'What's not hip in being successful?'     "So it all makes me resent English people now that I don't have so many big hits over here. But I'm a fool really because I love England best.     "The thing is, though, that you can make £300 or £400 a night in England and about £8,000 a night in the States."     But can he expect much popularity at home when he's out of the country so often? "This year we've been in America for only seven weeks. We've travelled elsewhere as well, of course, for, after all, if I'd stayed in England I'd be dead - as a name - by now. The only image we've got is that we're big in America. Beatles' mistake     "We made a big impression in America because we came in after the initial Beatles wave of hysteria had died down and they took to our broad Lancashire accents.     "I think the Beatles have really made a mistake talking about religion. It is a comment like this that makes me think of Elvis Presley.

"When I met Elvis last year, I deliberately tried to be a bit blase and Elvis was acting dumb answering 'yes' or 'no' to every question whether his answers made sense or not.     "It was Colonel Tom Parker who impressed me. When I left, he handed me a huge wrapped present. When I came to open it, it contained a copy of every record Elvis had ever made. That's promotion for you."     Promotion for Herman, however, as a sort of juvenile George Formby doesn't really please him. "I'm afraid it will go against me as I get older and try to make the transition from a young to mature artist. Only Tommy Steele has achieved it - and maybe Paul Jones will, he hasn't left it too late.     "I always want to be successful, you see. I've no desire to retire on the money I've already made."     He admits his life is hardly natural for an 18-year-old, but adds: "I'm an entertainer and I live and sleep it. I don't regret the life at all. I've had a better education and life since leaving school. Back in my schooldays all I thought about was money."     He does, however, invest a lot of money on the Stock Exchange. He keeps a close watch on share indexes, makes most of the buying and selling decisions himself.     Yet he says: "Money has put everything at my fingertips. I live good, I drink the good things, I have cars, I am buying a house in Switzerland (there's shrewdness for you!) and another in London.     "But money is just for staying alive. I don't need it for the things I want to do, like reading Dickens, Tennyson and Shakespeare, learning to dance, speak properly, play the piano properly."     Those might appear pretty unlikely ambitions for someone so conscious of success, keen on staying successful and contemptuous of fellow-artist critics. They're not - when the hard-thinking, intelligent-talking Herman can also turn around and, almost apologetically, add: 'You know, sometimes when I'm alone, I think to myself 'Here I am, still 18 years old and I've seen every place in the world' and then I really wonder whether something disastrous will happen to me. I've been so lucky up to now."