Very silly, but great fun.

Although it did give me some Fridge Logic issues from memories of other Silurian stories:

The Silurians went into underground hibernation when they spotted a body on collision course with the earth; this object became our moon. This would have happened long before the age of dinosaurs.

In another story, the Silurians had at one time invented a virus that infected apes, which they used to stop man's ancestors from stealing their crops. If they coexisted with mammals, this would be long after the age of dinosaurs.

So when did they manage to round up a few specimens to fire off in a spaceship?

This is most likely all explained away in the Doctor Who equivalent of Wookiepedia...