Siamp - overflowing

[linzeloo]

Looking for help to fix my loo please.
I'm unsure what model it is and can't find the exact on on the siamp website help pages. It's a bottom inlet type though and it either won't stop overflowing or when it does, it takes around 20 seconds of overflowing before it levels. I've tried changing the diaphram (which was split) but it hasn't fixed the issue. I've also tried lowering the float but despite sitting an inch below the water line, the same issue happens.
Plumbbase advised me to take it apart and check for debris in the internal valve but I can't figure out how to do this. I've taken apart as much as I can from the top mechanics (see photos). It's not one of the modern valves that has a nut / washer where the float sits as plumbbase stated.
Can anyone advise on how to remove it to check for splits of debris please?

Loo 1

• linzeloo
• 17 Dec 2020

Loo 2

• linzeloo
• 17 Dec 2020

Loo 3

• linzeloo
• 17 Dec 2020

 

[dilalio]

If you're sure it's overflowing the dump valve (which it looks like from the photos) and you have changed the diaphragm, then the best thing to do is change the whole inlet valve with a fluidmaster.

 

[CBW]

Looks like it may be catching on the cistern wall? Might be a height adjustable, or even twistable (be careful if you consider this route though as bottom connecting nut may become loose and leak), if it’s twistable you may be able to turn 90 degrees?