I’d set up the card as a Euro currency bank account in QuickFile without an opening balance, then tag the £157.95 payment out of your current account as a transfer to the card account - you should be able to set the Euro amount at that point. Your Euro purchases can then be paid directly out of the Euro account.
When it comes to your year end (or any other time when you want an accurate balance sheet) there’s an option on the bank account somewhere to record a currency gain or loss, which is a special journal which adjusts the GBP nominal value of the bank account without touching the EUR balance, putting the matching entry to “currency charges”.