The push button within a circular ring can be removed but the circular ring on the cover cannot be removed so the cover could not be taken out as the push device and pump are attached to the circular ring. Normally for other brands, the circular ring can be screwed out but for Bellavista, it is different. Anyone can advise.
You need to pry out the two push buttons. Then you'll find a screw underneath to release the top from the cistern cover.
Bob
January 2015
I tried what m suggested but it didn't work. I believe it's not meant to be screwed out. Any other ways it can be done?
Ron
October 2013
try spraying wd40 on the ring, it should screw open, try cut a wedge of wood and tap it down into the ring till its very tight , you might get a turn on it that way,