I’d like to use a certain default currency (GBP). How can I do that?
The great thing about using Oveit to handle your event registrations is that you get paid in fiat currency (conventional currency), not bitcoins, so you don't have to do anything. By partnering with Stripe, Oveit can allow you to accept bitcoin payments for your ticket sales.
You can change your default currency in Billing > Billing settings > Preferred currency.