GSXR Shock Respring and oil - Bladder questions

[Pigeon]

I've bought a second hand GSXR-1000 L5 shock with a hope to fit a stiffer spring and suspension fluid.

Reason being, carrying luggage and after an hour its lost damping. The rear then sits lower making it more uncomfortable.

I figured, I could have a go on this second hand shock rather than tinker with the one on the bike.

https://i.imgur.com/zPyjlaD.jpg

https://i.imgur.com/o3fsiDi.jpg

https://i.imgur.com/QVyMs2n.jpg

I've removed the spring, but before proceeding with taking anything else apart I believe I need to release the pressure in the Nitrogen bladder.
On my dirt bike there is a valve where this cover is.

But on this shock (same as my KYB on Striple), there is a cover with a small hole in the centre.
The cover is held in place with a circlip.
I need to depress the cover enough to expose the clip.
And this is where I would expect to release the Nitrogen to then be able to depress the cover.

However with no valve in plane sight. That little hole, when poked (thinking there might be a valve behind) feels very much like the rubber bladder itself. So at 165 PSI I don't really want to be poking it any more.


https://i.imgur.com/3GsQlJ0.jpg

The only other way I can think, is to undo the compression part using the very large nut here. Let the fluid out, then try and depress the bladder cap to expose the circlip.

But again. Dealing with 165PSI in the bladder, I'm not going to proceed until I can get some information from someone who knows.

I've been googling but have failed so far to find answers.

Any help appreciated as ever


EDIT:
Apologies for the images, not sure how I managed that. They look odd on my pc/browser.