Surprised to see the NQY flight award 375 miles (125 for discounted domestic, plus 250 tier bonus). Is the tier bonus based on the full 500, not the discounted rate of 125?
This seems a general award of 375 miles for a £9 (+tax fare).
Particularly considering that you only get 8 times as many miles (3116) on a single in J to DME, which costs 100 times as much.