When I drove over a bump my octavia seems to creak and its really annoying. I opened the boot and bounced the back of the car, I suspect it is coming from the rear suspension.

turn the radio up

I have an annoying creaking noise coming from the rear of mine too. Am going to lube the door lock, and the rear seat keeper mechanism. Failing that, I will bring it back to the dealers.

Hope it's not the ARB....