We present the highest resolution single-dish submillimetre observations of the detached shell source U Antliae to date. The observations were obtained at $450~micron$ and $850~micron$ with SCUBA-2 instrument on the James Clerk Maxwell Telescope as part of the Nearby Evolved Stars Survey. The emission at $850~micron$ peaks at $40arcsec$ with hints of a second peak seen at $sim 20arcsec$. The emission can be traced out to a radius of $56arcsec$ at a $3sigma$ level. The outer peak observed at $850~micron$ aligns well with the peak observed at Herschel/PACS wavelengths. With the help of spectral energy distribution fitting and radiative transfer calculations of multiple-shell models for the circumstellar envelope, we explore the various shell structures and the variation of grain sizes along the in the circumstellar envelope. We determine a total shell dust mass of $(2.0 pm 0.3) times 10^{-5}$ M$_{odot}$ and established that the thermal pulse which gave rise to the detached shell occurred 3500 $pm$ 500 years ago.
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