Help with drainage plan

[LiamJones]

How would you plan the drainage for this project? 

 

I was going to run all of the ground floor drainage down into the oversite and then straight out, underground, into multiple inspection chambers. I've now realised, however, that any below ground drainage will need to be dug under the existing foundations, the foundations are 300mm to 550mm below dpc. I'm now considering reducing the number of underground penetrations, and connecting more bits up inside. 

 

The kitchen sink is straight out already (to the right), as this is a new extension and was all planned for. But the utility, both bathrooms and ensuite i'm scratching my head with.

 

What would you do?

 

[LiamJones]

Could something like this work? Or is it too much for a single stack? Could i "daisy chain" some of them together to reduce number of connections into the stack?

 

[crooksey]

Should be fine, all down to what building controller is happy with. Probably look at it once and just nod. Two bathrooms upstairs and one downstairs on the same stack isnt un-common. Added utility sink and washing machine isn't adding much into the mix.