3rd time lucky. Windows 2000 installed from my disc, ran the BIOS update which cleared the BIOS password and now the machine seems to be running perfectly. Battery is operational as well, haven't got an exact run down figure but it's enough to take it off AC, hunt around for another one and throw it back on AC anyway.

For the record, the IT manager also has a Sharp Notebook (Pentium 1) and a Toshiba Satellite (Pentium 1) that he's also about to throw out. Worth picking one of these up?