How do i access my cistern?

I have got a concealed cistern in my bathroom. The dual flush is located on the front of the wooden panel, I thought to remove the wodden panel to access the system I would have to unscrew the flush buttton, but in doing so I have unscrewed the flush button and the back of the flush system has fallen off inside the wooden casing. Does anybody have any idea how the wooden panel is attached to the front of the cistern so I can remove it.
I don't know what make and model it is but I have included a link to a picture that looks similar to the toilet we have.

http://www.shopwiki.co.uk/detail/?q=Back-to-Wall+Toilet+Unit+Complete&s=331112&o=195911062&d=daVinci+>+Monte+Carlo+complete+back+to+wall+toilet+set+in+white

Any help appreciated
Many Thanks