You can change the currency either in the top right of the main page (on desktop format) or at the bottom of the dropdown menu, by clicking on the "€ EUR".

If you are going to be travelling around Europe I would advise you get a debit or credit card that gives fee free and competitive exchange rates. UK has a good market for banking so if your bank doesn’t offer a decent card someone else will.

You will get ripped off with very bad exchange rates if you accept payment in your own currency rather than local currency at many businesses and at ATMs for withdrawing cash.

Passes are generally a bit cheaper in GBP on https://www.myinterrail.co.uk/