Concealed cistern - removing flush valve

[CBW]

Good afternoon all,

I’m after some help on the above if anyone can assist? Customer stating that the wc cistern isn’t filling up and trickling into the pan, however I can’t manage to remove the flush valve. I separated the big plastic nut, however there’s not enough room to remove the bulky flush valve. I tried undoing the small brass nut in either direction to no avail. For some reason some of the parts are 2 brands - Missel and Grohe, the bottom half being Grohe, so I’m hoping it’s just the washer, but can’t remove to see if it’s perished.

Photos attached

Thanks in advance

 

[YMF]

Sorry I can help with your issue. Can you help with mine?! I have the same set up as yours - see attached pic. I am trying to replace the Missle inlet valve but cannot detach it. I have turned the nut (see red arrow in pic) both directions but it is not detaching - I think you had the same problem. Did you manage to detach it in the end? Thanks for any advice