In article ,
The Medway Handyman wrote:
dmc wrote:

Generally speaking, on the ones I have seen - push down one of the buttons
and you should be able to prise the upper button out, then the lower one.
There is a screw underneath.

Ah, that sounds plausable... ta

So, a) how do I get the top of and b) any suggestions what is broken
(is there still just somesort of dual syphon or is it going to be an
odd flap arrangement)

If it doesn't flush & the internal overflow is working, best change the
siphon & ball valve for new ones, not that expensive but takes a bit of
time.

K. Will have a look.

thanks,

Darren