Toilet Flush Button Stuck In

[Dusty Volunteer]

We've not long moved in to the house and today the button to flush the main toilet has decided not to pop back out. As you can see, there's no access. In the room backing on to this bathroom wall, there is a screwed-down boxed-in panel/unit at the back of the wardrobe. I'm hoping this is mechanism access but I have zero experience and would welcome any advice, or if we just need to call in a plumber.

 

[terryplumb]

Remove what you think is the access panel ,and show us pics of what's behind it....or call a plumber as you will very likely need to replace some parts.