I did this recently, with the 2 of us going JER-UK-DUB in CE.

BA wanted £627, which I thought was a bit expensive for what it actually offers these days. So I used 73,000 Avios to knock £400 off the cost. I make that £0.55/Avios, which isn't great. But OTOH we have a large Avios pile, and that saving just about covers the cost of 2 week's SUV rental in the US next month.