What Queensland vacation spot used to be called Umbigumdi (Umbi-Gumbi)?

Any chance you mean UmbigumBi? (Actually Umbi-Gumbi)
If you do then I think it is Surfers Paradise.

People looking at the high-rise buildings of Surfers Paradise today might not be surprised to learn that its original name meant, the place of the ant. (Umbi-gumbi in the Aboriginal language.) J.H.C.Meyer acquired land there in 1876 and established a sugar plantation and crushing mill near the Nerang River and ran a ferry over the river. In 1888 he built a hotel at what was then called Elston. That name was the maiden name of the postmaster's wife at Southport, bequeathed to the area when it needed a distinct postal address.

Growth came when the Jubilee Bridge was built across the Nerang River in 1925 and James Cavill, owner of two hotels and a sports store in Brisbane, built a hotel there to cater for fishermen. Prior to that there were only a few isolated shacks and a post office. He found that the beaches drew more people than the fish, so in 1933 he re-named his hotel The Surfers' Paradise and persuaded the authorities to make the same name change for the area. The hotel was burnt down a few years later, but rebuilt as a luxury hotel with a zoo and tropical garden

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