Great.
Thankyou for the detailed reply.
I took hundreds of photos along every stage, so hopefully that would minimise the opening up requirements.
Do you think a Building Surveyor would do pre-emptive…

No I didn't.
Something I don't need to do right now as I wont be selling for a while, but it would be nice to tidy up.
I might try

We had a kitchen/laundry renovation done 3 years ago which involved making the separate kitchen & laundry into one area and expanding into what used to be a under roof…