SEREL Toilet Lid stuck

[B Tolkien]

I've just moved into this house. It is a close coupled setup but the rear of the pan is enclosed with no visible access to the bolts holding the cistern in place or to the water supply.
The problem we are having is that the lid is stuck. It appears that the flush button mechanism is stopping the lid from being removed.
Can someone confirm that it should just lift off?
Any ideas on what is going wrong?
If I force the lid and break the mechnism , where can I buy parts?
Thank you

 

[franky]

unscrew the flush button or it might be a 2 button system where you press down one button take the other one up you should then see a screw underneath undo it.

 

[WHPES]

To clarify, with some you have to remove the buttons (with one pushed in the other one will pull out but you need to look at it carefully to work out if you need to prise them out with a screwdriver as they can have spring clips. There is a screw underneath when you have removed them.)