I thought they were catogory D (same as the nationals) which it what it said on their website, but now all the info has gone, and iv heard the points is just double points down to 15th, not down to 40th, which is catogory D, does anyone know anything about this?

Yep, what he said.  When people talk about it being "double points" it's just a lazy approximation, since 1st is now 60 points instead of 30.  But yeah, they go all the way down to 40th.

Who is eligible to win the english champs?

Does it overlap with the midland champs (i.e. someone from the midlands can win both) or is it strictly speaking the "english (excluding midlands) champs"?