Do we need a certificate of permitted development?

[CorpusCallosum]

Can anyone help me work out what applies in this circumstance....

We have planning permission in place for a project which would have included an attic conversion, 6m ground floor extension and 3m first floor extension.

After we got planning in place we contacted builders and found the big project was just too expensive. We booked to do just the attic instead. We're now looking at doing just the ground floor too, out to 6m. Both of these would be covered by permitted development so we don't need new PP, but, do we even need a certificate of permitted development as they're part of the existing PP?

It would save us some money & time if we don't and I can't find a straight answer online 🧐

Worth contacting your council but my understanding was that the PP, covering attic, ground and first floor extensions, covers this. So no PD certificate needed.

6m ground floor extension is only PD if you've been through the neighborhood consultation process. Which sounds unlikely. I think you need to get your approved planning permission amended.

Get advice from your council in writing as if you have any question marks it can cause delays and potentially issues if you sell in future.

It might be permitted development but if you're going out over 4m I thought you needed prior approval? You might be able to submit a non-material amendment to your existing planning proposal to reduce the size of your extension?