I think the danger with using the term 'trilogy' is that it sets up particular expectations in the reader's mind.

I think I'm highly loveable.

I think I set myself on a course to become a scientist around about the time that Carl Sagan's 'Cosmos' series was on television, and there really was no going back for me at that point, and then I went on to study space science and then get my Ph.D., then go aboard and work in the European Space Agency.

When you're writing stuff that's already clotted with neologisms and trying to get across fairly abstruse concepts, you're already putting a heavy burden on the reader.

I don't think these particular earnings are going to mean much for the market in the short term.

I've never had much interest in spinoffery - the idea of writing in someone else's universe generally leaves me cold - but 'Doctor Who' is different. I've grown up with it. It's been part of my life since I was tiny, watching Jon Pertwee on a grainy black and white television in Cornwall and being terrified out of my mind.