I have no information about a previous British performance but it was definitely not a world première. A Rome performance dated 5 December 1953 with Herbert von Karajan conducting the Rome RAI SO and Bruno Giuranna as soloist can be found on youtube.
I do not even know for sure if this was the world première but, given the composition date, it seems likely and at least one reference book lists this among works premiered by Giuranna.
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