Given the law in the UK at the time (1950s) it's understandable why he'd want to leave.
I don’t recall when Clarke departed England. My gut says it was some later than you suggest.
I seem to recall Clarke did change his writing focus from “outer” space to “inner” space somewhere in the time frame you suggest. I recall he did author a “youth series” dealing with the sea starting around then. “Deep Range” is one title I recall.....
But Clarke’s pen/wit sdpanned a wide scope from humor to strict science to fantasy. His Tales of the White Hart are an exemplary diadem of the short mystery story; every one based upon strict science....Often containing a subtle pun in the titles. “The Defenstration of Ermintrude Smith” is an excellent example...... >PS