MACDEE CNEU COMPACT 6 LITRE FLUSHING PROBLEM?

The Gromit which the tube from the push button goes into has come out the hole it fits into. This is because i had to try and remove the tube to let the push button back out. This has been a recurring problem. Do i need to replace all the flushing parts or is it possible to remove some parts to allow me to fix the gromit properly and do you think this would solve the button sticking in?