Hi Steve
The half and full flush silver buttons pop "up"
First press\hold down the larger button which reveals part of the smaller button.
You can then get your finger under the smaller button enough readily push it upwards.
Then taking off the full flush button is easy.
From there, a plastic flat head screw is revealed which once unscrewed, enables the silver cover to be removed, and hence the entire cistern cover simply lifts off.
Arfee
September 2010