How do I upgrade to First Class on Avanti?

You can upgrade your ticket to Standard Premium whilst onboard the train that you're travelling on. Simply speak with your Train Manager and request to purchase an upgrade to Standard Premium on your day of travel.

Is Avanti First Class worth it?

For me, travelling First Class was worth it just to get a more comfortable seat in a quiet and spacious carriage. I was also impressed by the food and drinks weekday service on the outbound journey, which made the 4-hour + journey fly by.