From memory the going rate for a reasonably well specified Plus 4 in 2016 with necessary options was circa £44k.
More extras makes the car sell easier but not above the average.
So 50% depreciation in 8/9 years selling to a dealer in a market awash with Morgans.
There are still not many cars with that return in my opinion.
It's hard but the glory days of Morgan residuals have gone - at least for a while.