I've been reading and enjoying this and haven't had time to comment before now. :P I do like the use of snippets from Doomsday at the beginning of each chapter, and the Doctor and Rose working together to solve his dilemma.

But am I understanding this correctly? Rose is supposed to be driving from London to Cardiff? Torchwood is in the East end of London (Canary Wharf, in Docklands). It'd take about five hours to get to Cardiff from there by car. An hour, in little to no traffic, just to get to the other side of London! My husband occasionally drove from Slough to Cardiff and that took him three and a half hours, and Slough's about 40 minutes to an hour from central London. Canary Wharf's way over to the east. So, unless I'm misunderstanding what you're doing here, you might want to rethink that. :/