Trouble removing vertical header

[Two dogs]

S2R1000 full Arrows and an Ohlins DU 333 rear shock with remote's
Removing all the headers to polish and I have run into an issue with removing the inboard
nut on the engine that holds the header to the cyclinder .

The gap between the rear shock linkage and the end of the stud is so small once I get the nut to the end of the thread I cant get a tool to get it off. Using a ratchet ring spanner , socket wont fit in either 
Had the bike on a rear stand and on the ground , made no difference to the gap. 
Any suggestions would be appreciated .

[ducpainter]

Support the bike and pull the top shock mount.

[He Man]

^ what he said. I dont know if theres another way to do it, but none of my tools fit either, i just remove the top shock and move it out of the away.

[Two dogs]

Thanks for that He man and ducpainter