Data point; at 14:50 Wednesday 8th April I called 020 3250 0145 and successfully got into the queue through option 2-2-2. Wait time 16 mins with a lovely agent who had no qualms sorting a refund for a cash + Avios part pay booking. She advised refund to credit card would take 10-14 working days. Total call time 24-minutes and Avios are already back in my account!