The word as used in the following excerpt doesn't involve wandering in a leisurely way, but there is something quite unexpected in this instance of bimbling from Sam Lonschein, My 83 Years: The Memoirs of a Veteran Zionist (1967) [combined snippets]:
The only bulletin notice in front of the building had his name written up by hand. The few friends whom I had sold about six tickets looked at me with suspicion. We sat down. Soon the artist appeared. Bowed graciously and sat down at the old piano in the middle of the stage. He threw his head backward and began to play something, but none of us understood what it was. After ten minutes of bimbling and moving his fingers over the instrument he stopped with a bang and stood up. There was little hand clapping from the first row. (All his relatives were in that row). He went backstage, then came out again and this time he played a Rumanian popular piece. It was a complete fiasco. The few people (strangers) walked out in disgust.
A few weeks later when I saw my printer friend he told me that Conrad Bercovici was not a pianist at all. The concert was arranged by his family to get together a few dollars as he had come over penniless from France to try his luck as a novelist in the English language. He also informed me that the "Tageblatt" had bought a story from him for $10.00 which they were now translating into Yiddish to be printed in some future number of the paper.
This is the story of the well known gypsy story novelist, Conrad Bercivici, who became famous in later years as a fiction story writer.
In this instance, bimbling may be a typo for bumbling, or it may be a neologism of the author's to describe a kind of aimless but exaggerated attempt to play an instrument without really playing it at all. In any case it seems highly unlikely to have had any influence on the emergence of bimble in the Falkland Islands 15 years later.