Moen shower cartridge replacement & plastic plaster guard

[Amateur2]

So I need to replace the Moen shower cartridge in this valve, but I'm not sure how to proceed.

The plaster guard was left in the wall by the original installers, probably because of the thin wall installation.

It seems like the silver sleeve & the locking clip are blocked in all around by the plaster guard.

Do I need to cut the plaster guard out & compromise the seal with the escutcheon?

There is no access panel currently to add valve support behind this & I'd rather not make one if possible.

Advice appreciated!

 

[Terry]

Thin wall would have been fiberglass. Go ahead and either remove the plaster guard or notch it to access the clip for replacing the cartridge.

 

[Sponsor]

 

[Amateur2]

I removed.

Thank you, Terry.