Mix and Control not working in Logic Pro X 10.4.4 after OS upgrade to 10.13.6

[Craig Hume]

Hoping for some insight or maybe I've reached the end of the road with my Euphonix branded Mix and Control and Logic?

All working fine in Logic until recent OS upgrade to High Sierra 10.13.6. After this, although 'Logic Pro X' shows as the application in use in the top left corner of the Control window, no other functions are recognised and both units are dead. Both units show as 'My Surfaces' in the EuControl settings window on my mac.

EUCON latest 19.5 was downloaded as I believe I was on the previous version of 18 to try and rectify but still not working.

I'm a little out of touch with how far Avid are supporting this hardware with Logic these days so apologies in advance if this issue is well known.

Thanks.
Apple iMac 27-inch with Retina 5K , 3.1GHz 6-core 8th-gen. Intel Corei5 ,8GB, 1TB FD, Radeon Pro 575X z 4GB
High Sierra 10.13.6
MOTU Ultralite MK3
Logic Pro X 10.4.4