Cheers wombat81; yeah, I had reached out early this week and asked a few questions and for timings, and their estimate plus postage time was fair. Lucky enough to be able to borrow a vehicle for the timebeing and COVID-19 means I can't get out and around much anyway. The actual unit swap looks easy enough and I do have the Toyota Workshop Manual on-hand.
Regarding the 130A OEX, I trawled a lot of the topics re: alternators and general consensus was that 130A does warrant a wiring upgrade but I didn't find anyone who actually had issues with their 130A unit. Mudgeeraba do have an
aftermarket 150A option on their website and a kit to go with it which also looks quite simple if you wanted an idea of what you're looking at.