How do I remove a Vitra toilet seat to tighten one of the hidden screws under the chrome covers? There are no obvious screws to remove. Just moved into the house so not sure of exact model - it's square with rounded corners. Any help would really be appreciated thanks.

I finally figured it out! The vitra soft close toilet seat I have, I couldn't pull it up, and there were no buttons to press to release it upwards.

For my soft close toilet, there are caps on top of the fixings, which you need to PULL out (ie pull sideways towards the middle of the seat). Once you slide off the caps, you can pull upwards on the toilet seat to remove it. Then you can remove the chrome covers, and find the screws underneath the chrome covers.