I ended up going through with the belt mod (thanks to Sidereal Trading for getting it out so quickly) and also took the opportunity to replace the worm gear bearings with SKF and re-lubricate everything with Super Lube.
I was a smooth process. I can feel a lot less backlash in DEC now (I can't physically wobble it like I could before). It's also much quieter and smoother.
Haven't had a chance to try it out in the real world yet as we've got nothing by clouds for the next couple of weeks in Melbourne
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https://i.imgur.com/6S3KZBD.jpg
https://i.imgur.com/kwc2PML.jpg