I am in a similar position. Recently had to cancel the return half of a 241 long haul due to a medical issue. Cancelled 48 hours prior to the return flight. They waived the change fee so I pushed the return back to almost a year after the outbound was flown to provide a chance of using the ticket in the future rather than just losing it all. If I ultimately cancel it, I know the Avios will be lost but can the fees be refunded? It was RFS pricing and had a charge of £475 so worth fighting for if possible.