Now I hooked up my Corsair Xeneon Edge screen, I could monitor the temps more closely and noticed the CPU (7600X3D) was sometimes running a little toasty. I tweaked it as far as I could in terms of undervolt, but this specific chip does tend to run hot in other chips, to the point whereby I wondered if something was wrong with it because my more powerful 9800X3D runs so much cooler.
Anyhow, I removed the top panel to see if it made a difference and it did, by almost 20C.
I would ordinarily do this myself, but haven't had the time so 2 days at the local car body shop, and £50 cash later, I had the top panel modified, so having more holes in to allow more airflow.
With it on it runs about 15C cooler than a before, so it's making a difference. I only asked the body shop to drill some holes and smarten it up, but they followed the pattern from the front panel, which I also gave them for reference. So really happy with what they did.
Old panel:
New panel:
