Fluidmaster replacement button (older version?)

[neate]

I have fluidmaster dual flusher. The original dual flusher button broke. See image 1.

The shaft of it sat snugly into and within the top of the cistern and was tightened up from underneath. See image 2 where I've highlighted in black the tightening plastic screw device.

I ordered another online only to find that it perched on top of the cistern and the tightening plastic screw barely tightens it securely because the entry hole is too wide. See image 3. It works but there might come a time when it is knocked and I have to redo it.

Tool station and Screwfix only sell the one I bought online. I must have an older version. Does anyone know where I can get a replcement button as per images 1 an 3?

 

[Elkato531]

The new button should come with a removable tapered sleeve (chromed plastic) which you throw away if not required.

 

[Elkato531]

 

[neate]

How simple. I must investigate. I'm much obliged Elkato531.