Unfortunately, it does sound like the thermostat housing issue, based on year and mileage. Clearly not an accurate diagnosis on the internet.
On a slightly more positive note, VW are aware of the issue.
If the car has VW service history, there is a very good chance they will help with parts and a contribution to the labour cost.
The assistance offered is down to the dealer and how effective you are at expressing your level of "disappointment".