I work for VTWC at the moment in their CR department but was recruited alongside some welcome hosts and First Class hosts too.
The recruitment process for us was a video interview which was reviewed, and based on that you are invited to their Crewe training centre to undergo a day of competency in terms of your English ability, etc. Hopefully once you're passed that stage you will get the job and spend 4 weeks back in Crewe training in all sorts of customer service environment, learning about tickets, and all that fun BTS stuff!