Yes, a refund is calculated from the difference between the price you paid for the Flexi Season ticket and the cost of an Anytime return ticket for each day you have used. You must apply for a refund before the end of the 28 day validity period. There must be a minimum of two unused day passes left to refund and a £10 admin fee will apply.
Simply log in to your online account, select 'manage my tickets/refunds' and follow the steps to process your own refund. Your refund will be made in the same way you paid for your ticket. Please note, there will be a £10 admin fee.