Monday 12/1
LHR-IAD WT+ to CW: £599. Not proactively offered: I had to ask. I took up the offer.

Wednesday 14/1
IAD-LHR WT+ to CW. $850, Not proactively offered: I had to ask. I didn't take up the offer.

Both original tickets were booked as redemptions in WT+ (a great use of Avios being reducing the cost of mid-week TATL flights!).