On Aug 16, 1:41 pm, John Rumm wrote:

You can if it is easier, change the stack from CI to plastic half way
up. So you could switch to plastic and add a new branch in that.

That'd be great. I'd like that, because I bet one of these:
http://tinyurl.com/2wqwpy is not cheap.
But it seems like swapping plastic into cast iron stacks really isn't
approved of in this neck of the woods.
One plumber and the building control guy concur on this.

I could just do what I wanted, but then might have problems selling
the house if I've done something easily visible that's not allowed.

This was building control you were talking to and not MI5!

Just kidding about the call tracing.

If you are going the building notice warrant route, I would phone them
again and ask about how they handle part P. Make sure your council is
not one that will try to stiff you into paying for an external test
report - because that could add another couple of hundred to the bill.

Part N up here, I think.
Frankly I'm becoming resigned to hundreds being added onto the bill.
After all I need to interact with the government, and trained
professionals, sob.