I had my last Ully Shock rebuilt and they upgraded some valves or something inside as I used the bike two up with luggage a lot of the time.
After it was done it was much much better when loaded and not silly stiff when riding on my own, it cost me £165 from a place in Stowmarket Suffolk called MCT Suspension.

I have a bit of a theory regarding the rear shocks, I think when the bike is loaded and two up for the first 10-15 miles the shock handles okay but then it gets more and more bouncy the further we ride the bike.
I think it maybe the fact that the shock gets hot from the engine heat and the fluid thins out, I maybe wrong but this is my second Ully and its only done 10000 miles and it does exactly the same as the last Ully regarding its performance.
As the shock gets hotter and more and more bouncy I used to turn the preload up and once it got to max I then turned up the damping etc to max in the hope it would cope but it never did!
Once I had the upgrade done it was no longer an issue.
Well that's my theory some of you may disagree I don't know but what I do know is I will have my current Ully upgraded this year when I get the time

"SimonD"]I'm thinking of changing mine because it all gets a bit floaty/bouncy when pushing on. That one looks like a backward step from oe.

There is a reason for going backwards, I should have explained things more clearly.
At the moment i,m changing the ULY to give it an STT/SS look.
This has meant the relocation of the ECU and BAS asI want to keep the uly undertray.
This shock although cheap and probably nasty was gonna free up space in the undertay next to the battery as there is has no separate reservoir to mount.
I rarely ride 2 up so I could have a custom spring made for my weight and no rebound/compression adjusters to twiddle with. Then fit and forget.
After all the helpful advice im gonna get the oe shock rebuilt at MCT Suspension (Thanks Gibbsy)