Ok, I built it!
But, I 've made some modifications because these are the parts I had in hand.
I avoided getting out of the house (corona virus, you know).
So, I replaced Q2 with a DIY darlington pair, with BC557 & S8550.
Q3=Q4=D209L.
D5=BAT41 (instead of BAT85)
I did some tests, with no current limit:
RL= no load, Vout=16.79V
RL= 20 Ohms, Vout=14.93V, Iout=0.71A
RL= 10 Ohms, Vout=13.59V, Iout=1.26A