Hogfather questions

The Hogfather

Anyone else watching The Hogfather on Sky One? Anyone who’s also read the book? I have some questions for you then:

  1. Why is Marc Warren doing an impression of Peter Lorre, but Peter Lorre if he happened to be Dutch?
  2. Is Terry Pratchett a big Doctor Who fan? Susan, the granddaughter of a mysterious figure with power over time, who just wanted to settle down for a normal life: sounds familiar.
  3. Is the massive “next time on The Hogfather” trailer shown at the end of the first episode possibly the biggest spoiler ever seen, or are there any surprises at all left for the next part?

Thank you in advance for any help you can provide.