There's some great info in this thread well done to all who have supplied information for novices like myself.
I'd like to clarify a few things (in summary of 700+ replies):
1: I'm operating a Columbus system in a 2015 Octavia using the latest 2023 maps therefore I believe this to be the Mib2-High format. As a result the only way I can effectively receive TMC updates is to invest c. £100 in one of these kits https://obdeleven.com/products/pro-pack (admittedly there will be other uses for it in fault diagnosis etc) and change some settings.
2: My wife's car is a 2017 Fabia operating the Amundsen system with the latest 2023 maps. The options for this would be to revert to using old maps or subscribe annually to the Skoda Connect system which would involve eating her mobile data or investing in a sim only data plan via an in car stick.
3: This one may be contentious but Skoda's (probably should label this as VAG's) decision to move to Tom Tom as a map supplier has partly caused this issue as Skoda's base data is locked to TrafficMaster system. Although it was TrafficMaster's decision to stop transmitting the information rather than Skoda's to stop receiving it their decision to lock the data has further impacted the issue resulting in many vehicles Sat Nav systems, although not necessarily being obsolete they are no longer fit for purpose despite being only 7yrs old.
Apologies if this is going over old ground.