Trying to put wall hung toilet back on after tiling

[BigBearTed]

I had a new Villeroy and Boch wall hung toilet installed a couple of months ago. Last week I had a tiler come to tile the cloakroom, he removed the toilet etc and tiled the room. I have to refit the toilet and now the distance has increased by 1cm. It's fixed by a securing frame behind a stud wall which I have no access to. Two threaded studs with end caps to fit to the toilet protrude through the stud wall plasterboard into the cloakroom. The securing device is held in place when activated by turning hexagonal rods from underneath )(not: NOT top fixed - these are operated from below the back of the toilet bowl). I have adjusted one of the studs to protrude 1cm futher into the room, by simply removing the end fitting to reveal a slot in the end of the bolt and turning it with a screwdriver. Simple. On the other side I cannot remove the end fitting. I can turn the end fitting in both directions and it just turns both ways without moving in or out. I can see it has a nut behind it, which isside the plasterboard, but all my efforts to hold the nut still and unscrew the bolt haven't worked. I've tried force (Mole grips and a flat screwdriver to try and brace the nut, even wd40 although everything is brand new. ) Yet the other side is fine. Any information or ideas would be much appreciated. I'm told that I might have to cut away the plasterboard and get a spanner on the nut. I can't access anything except from the front. Any information or ideas would be much appreciated. Thank you!

 

[Wayners]

Ring spanner over shaft onto nut?

 

[BigBearTed]

Thanks for the suggestion. Difficult to get it on the nut as it would have to travel over the end piece first, which is a bigger diameter. I'm thinking I'll have to cut away more of the back board and try a spanner.

 

[Wayners]

Maybe something like the Milwaukee flat jaw oong nose locking pliers might get a hold?