Many year ago i saw a sort of lifting system that you can lift a person from ground to the seat level safely!
In a BH206/407 on standard skid not a problem but on EC350 it can be difficult!
With a small electric motor or hydraulic (i do not remember!) you driving a side platform fixe on the machine and when finish it small enough to fit in the bagage compartment.
I look at GOOGLE but no success for now
not exactely what i'm thinking!
What i can remember it's a sort of inclined colon 5feets long with a slut on front side with a long screw inside,this screw is activate with a motor and take slider up or down this is where a seat is install.
the colon was probably fixe to the skid or the floor of the machine with pushpin.
Hope that is understandable!!!