pump replacement is a simple DIY task, it is as straighforward as you imagine it to be... sounds like ur system is depressurised by now, but remove pump fuse to make sure.
If you are in no rush, i would buy new from the UK. I would guess new pump to cost around 400AUD delivered to your door. might take a week or so to arrive.
If you are in a rush, then your hands are tied. Personally I would buy new, unless you are of the view that you will onsell your car within the year. Pumps are a known issue with selespeed. Yes prices in Aus are expensive IDK what new cost is here? $700+ fitted?
If you consider that $200 deal, i would ask if the motor has been reco'd with new electric motor bushings... may be the go w/ 1 yr warranty. But you also gotta consider the hassle.
btw, what yrs is yours? are u a member of aroca vic? should probably come down to the lcub nights, i'll be there tonight.