Pensfan,
I just downloaded it to check. The region asset itself is not faulty, but it has 3 dependencies that are faulty. This is apparently enough to stop it listing in Surveyor. The faulty dependencies are;
<kuid2:524343:6639:1> car 28 UK - Van_ford_e250s
<kuid2:524343:6642:1> Car 31 -Jp- car mazda rx8
<kuid2:524343:6643:1> Car 32 - Jp- Car Mitsubishi Magna
They are all cars by Arraial and refer, in turn, to 3 of my Kind scenery vehicles. The latest versions of those no longer have nightmode which is the root cause of the fault. If Arraial was still around, he could change those dependencies to point to my traffic-enabled versions of the same cars, but I don't think he's active in Trainz any more.
My suggestion is that you edit the Region config and remove references to those 3 faulty kuids in both the car list and kuid-table.
Be sure to identify them by kuid, not by car number, because the numbers above (car 28, 31 and 32) don't correspond to the numbers in the config car list and kuid-table.
Once you have done that modification and submitted the Region in CM, the Region will show up in the list of regions in Surveyor/Edit Route menu.
.