If you’ve take off the pre-load caps then it will almost certainly be that. I remember when you’re wife got the bike as you/she posted it on here. If it’s not had a service since you bought it, then it’s prudent to have one now as I think it’s getting on for 12 months old IIRC?
If you don’t think it needs one and want to try sorting the pre-load cap problem, then here’s a quick run down for how to do the BB pivot one.
It is possible to do this without removing the crank set but it’s a bit more of a faff.
Undo the two grub screws that bisect the pivot from the back of the BB shell; back them out maybe one full turn or a bit more.
Put your allen keys in on both sides, I think it’s a 2.5mm on the drive side and 4mm on the left.
Holding the non-drive side stationary, unscrew the right hand one until it is almost all the way out.
Now hold the drive side stationary and screw the non-drive side in until you feel the whole thing compress together.
It should really only be finger tight; hard to judge without experience, but it will come with time. It’s also a lot easier to judge this without the shock in as you will know if it’s over tight as the back end will feel distinctively stiff.
Note that Nic’s don’t have super free movement in their rear triangles even without a damper in; there is still a bit of stiction, like a Turner 5-Spot has.
Once you think you’ve got it tight enough, but not over tight, put the bike on the floor (with damper and wheels back on of course!) and test the back end for play. If there is some, then just nip the non drive side up again, making sure you also have the drive side allen key still in place and holding it stationary.
Repeat until there is no more play.
Finally, when everything is sorted, don’t forget to do the grub screws up gain!
Ride and enjoy.
p.s. I just got my new fully tailroed Helius AM (as well as a new son!) Happy Days.