FlyerTalk Forums - Refund award flight part paid with cash

I booked a short-haul award. I'm European based, so the cost was 4500 miles + €21 reward flight saver fee. At checkout I elected to select the option to pay 2500 miles + €20 + €21 reward flight saver fee as well.

If I wanted to cancel the flight and BA's cancellation fee for mileage tickets is €42.50 - if I had paid 4500 + €21, my cancellation fee would have been capped at €21. But because I paid €20 for the miles, does that mean my cancellation fee will actually be €41, or is this capped to the Reward Flight Saver Fee?

When I tried to cancel this on MMB, it does not tell me the amount it will refund (unlike cancellations of regular bookings), only that it will inform me of the appropriate refund after I submitted it. I have talked to an agent, but she says she doesn't know, and that the refund department will determine it once you submit it.

Does anyone have any experience with this? It's a minor difference, but I just want to change the arrival airport from LCY to LHR now that space has opened up - something that's not really worth giving up €41, but I might consider it if its only €21!