First things first- please dont take this the wrong way and assume i'm trying to pirate the software.

With that out of the way, here's the scoop- my ToB disc is getting more and more scratched, every time i use it, it spins quickly then stops dead, and gives itself a new scratch. Occasionally when i run the game it tells me the disc isnt present and needs to retry.
Since it is impossible to get hold of new discs, is there a way i can run the game without the disc inserted? It's on a full install anyway and never has to read anything from the disc, it just seems to require its presence. Ideas?

Well, yes... you're basically asking for a no-CD crack. But unfortunately such cracks are something we can't condone of on SP because most people use them to bypass copy protection, sorry... You'll have to find it somewhere else.