Replacing plastic with tiled...

[kiter1]

Hey
Just bought a Victorian terraced with a polycarbonate utility roof.
Its awful!!!!
I want to change it to a proper tiled roof with a couple of sky lights.
I have tradesmen in the family but not a roofer. I understand roofing just haven't done any. As far as i can tell its just going to be a wall plate on either side at x angle, joists hung between, board it, membrane, baton then tile. The only bit I'm worried about is the lead work and if i need to use cavity trays??
One wall does not belong to me so cavity trays is a no no really.
Anything i need to know before i get stuck in??
Any comments/help would be great
Cheers
Dave

 

[noseall]

building control - reg's?

 

[kiter1]

I want to do it all by the book and want the drawings i put in with my building notice to be right hence the questions.
Thanx
Dave