Hi and welcome to the forum - there are a few methods for removing those ghastly windows, but I think an angle grinder and a bunch of patience would be best. Even if theyre in OK condition, aesthetically they are pretty bad I reckon. One friend removed his and replaced them with timber windows. Biggest challenge was ensuring structural support throughout the project but once that was done, it was pretty straightforward.
BTW I have some pics somewhere of a stunning "1863" bluestone home in Brunswick that you might be interested in seeing, just for interest's sake. .... it started out life as a 1963, cream brick venereal with steel windows - even fooled my architect mates when I sent them to see it- let me know if you'd like to see them and I will try to dig them up..... the pics not the architects