Creation of Driveway - Soakaway or use existing drainage?

[DaveFix]

My front garden slopes down towards the highway. I would like to build a retaining wall and dig the garden out to create a PIC driveway.

I understand that creating a non-permeable driveway greater 5²m would require planning permission. As the footprint of my car itself is over 8²m I've recently submitted a planning application for the entire project.

In my application drawings I've included gullies at the driveway entrance draining into soakaway crates. However, I've never done anything like this and starting to wonder if I'm making more work for myself than is necessary. Is a soakaway really necessary?

Rainwater from the roof and from the concrete paths around my house drain into the water authority's surface water drainage system, and a portion of my water bill is paid for this.

Can I instead drain my driveway into the existing surface water drainage system as well?

 

[blup]

There are exceptions to the rule but generally its a no no

Blup

 

[Dereekoo]

As Blup says sending more surface water into already overloaded systems is tabood by the water authorities