Considering the school's connection runs at 2 megabit via fibre, and my home ADSL connection has an upstream connection of 160 kb or something like that, the connection speed should be close to what I get at a school terminal anyway.
Dad's a bit concerned about the power usage of running a pc 24 hours a day, so I think i'll put something fanless and energy saving together- possibly a mini-ITX box or something, and run this. Dad also only seems to use the connection for internet banking, e-mail and other stuff, so it's a bit overkill anyway, and he shouldn't mind the bandwidth usage too much :)
Cheers to all that have replied- I shall keep you posted on how it goes with all.
Dave.