Hi Malcolm,
I can see perhaps why you say that since they do have a similar likeness although I do in fact believe it is M83 due to the three Mag 10 stars in line to the west of the galaxy which point directly to the much brighter 7 Mag star HIP66539.
This configuration tells me for certain that it is the Southern Pinwheel Galaxy.
It can be confusing at times with so many similar looking fuzzies in the sky
Clear Skies,
Anth10