Okay so GIC is absoluty amazing. And your writing style is pretty good. There's only a few errors that were most likely typos. My only concern is that there is no merlin but its your story and you get to decide whether or not to put him in. I would suggest some foe the characters could face but I'm unfamiliar with doctor who. However if you plan on adding non alien monsters I can help you there. One thing that would be hard to beat is a Hydra. Its a seven headed lizard. If you cut off one of its heads, two more grow in its place.