Sure: here are some photos of both hinges from the top and from the back. And also of the underside of the bowl, showing the two holes mentioned with a hexagonal rod slightly emerging, but no nut accessible.
I've tried pulling the lid directly upwards, trying to slide the hinges in all directions, put oil on them.
The focal point of the image underneath shows inside the toilet. So if there are screws in there, I've no idea how to access them. You'd need some specialist tool, I imagine?
Thanks: I looked at this and it mentions "Lift the chrome disc." However my seat is different it seems - the disk on mine isn't a cover, but clamped firmly to the toilet bowl. I've even tried using a screwdriver to prise it up, in case, but no movement.
We have two bathrooms with Ideal Standard toilet seats. One you can remove the seat by simply undoing hexagon socket bolts with a small hex key. The other seat has no visible bolts and I've no ideal how to remove it. Even Ideal Standard couldn't help. They said simply to pull the seat upwards...