Displaylink-debian, post install problems

[electron1948]

Linux Mint 20.3
displaylinlk-debian 6.0
i_tec U3HDMIDVIDOCK
Installed without errors after lots of false starts.

All HW tests OK under Win10.

What I see on startup:
Green light on dock is on during boot but goes off when off when Mint opens.
Only one ext monitor found, VGA in HDMI socket with adaptor, labeled 'HP 20" DVI-I-1-1', Screen is black
DVI monitor not recognised at all.

Debug output:

---

Distro: Linuxmint
Release: una
Kernel: 5.4.0-177-generic

---------------- DisplayLink info ----------------
Driver version: 1.14.4 <--------------------- But V6.0 installed!
DisplayLink service status: up and running
EVDI service version: 1.14.4

------------------ Graphics card -----------------
Vendor: i915
Subsystem: Graphics
VGA: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 09)
VGA (3D):
X11 version: 1.20.13-1ubuntu1~20.04.17

-------------- DisplayLink xorg.conf -------------
File: /etc/X11/xorg.conf.d/20-displaylink.conf
cat: /etc/X11/xorg.conf.d/20-displaylink.conf: No such file or directory <---------------- There is no xorg.conf folder
Contents:

-------------------- Monitors --------------------
Providers: number : 5
Provider 0: id: 0x44 cap: 0x9, Source Output, Sink Offload crtcs: 3 outputs: 2 associated providers: 4 name:modesetting
Provider 1: id: 0x14e cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting
Provider 2: id: 0x12c cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting
Provider 3: id: 0x10a cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting
Provider 4: id: 0xe8 cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting

Any assistance would be most gratefully received!

Bob Fearnley